3

Changing Program Emphasis for Earth Venture Missions

As part of the flight program of NASA’s Earth Science Division (ESD), Earth Venture (EV) has always been aligned with the division’s overall objective to “understand our planet’s interconnected systems, from a global scale down to minute processes.”¹ However, while noting that some overlap is possible between selected EV missions and those outlined in the Earth Science and Applications from Space decadal surveys, early EV selection criteria also stated that the “Earth Venture class is not intended to be a mechanism for accelerating the implementation of [2007 Earth science] Decadal Survey missions.” Most recently, the importance of the EV program in fulfilling the objectives of the 2017 decadal survey was stated explicitly.² As the decadal survey also has as an overall objective the advancement of Earth system science, this may be a difference without a distinction; however, the explicit addition of selection criteria tied to the decadal survey is notable.

In 2021, NASA selected Investigation of Convective Updrafts (INCUS) for EVM-3. INCUS is designed to study convection and extreme precipitation processes and is very much aligned with the 2017 decadal survey recommendation that NASA implement a mission to address the science targets of the designated observable,³ clouds, convection, and precipitation. Such alignment does raise the potential that future PIs could see synergism with a listed priority mission in the survey as being central to the selection process.

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¹ See the NASA Earth Science webpage at https://science.nasa.gov/earth-science.

² See NASA, 2020, “Announcement of Opportunity, Draft Earth Venture Mission-3, Earth System Science Pathfinder Program,” NNH20ZDA006J, April 10, which states, “For this solicitation, NASA will prioritize consideration of proposals that address the questions laid out in the 2017 Earth science decadal survey and will use the classification of the question being addressed as a guide for consideration.” Observables that were deemed to be considered for Explorer Class (ES) Investigations and those listed in Table 3.5 as “Other ESAS 2017 Targeted Observables, not Allocated to a Flight Program Element” will be considered here as there are no assurances that all of these particular observables would be addressed in the near future.” Also stated in the 2021 EVM-3 AO is the following: “For this EVM-3 solicitation, NASA places a strong emphasis on research and innovation for Earth system science issues, especially those observational objectives given high priority in the 2017 DS, while expecting appropriate attention to applications-oriented aspects to further the overall value of the mission.” See NASA, “Earth Venture Mission-3 (EVM-3) Acquisition Home Page,” https://essp.larc.nasa.gov/EVM-3.

³ NASA requested that the 2017 Earth science decadal survey “recommend NASA research activities to advance Earth system science and applications by means of a set of prioritized strategic ‘science targets’ [expanded by the steering committee to be science and applications targets] for the space-based observation opportunities in the decade 2018-2027.” The decadal survey steering com-

Designated observables and Earth System Explorer Missions in the 2017 decadal survey map to a set of science priorities listed in that document. However, they are only a subset of a larger number of science targets that would have been prioritized by the survey had it been possible to accommodate them within anticipated budgets. Furthermore, those science targets are themselves the result of a prioritization from a still larger set of science priorities highlighted in the survey report.

RECOMMENDATION 3.1: To encourage consideration of a wider set of ideas benefiting Earth system science, NASA’s Earth Science Division should, in future Earth Venture solicitations, emphasize that science priorities of potential interest encompass the full range of science priorities in the 2017 National Academies of Sciences, Engineering, and Medicine decadal survey Thriving on Our Changing Planet: A Decadal Strategy for Earth Observation from Space.

The EVM-3 AO included the following changes relative to earlier calls for EV-M:

• AO cost cap increased from $166 million (fiscal year [FY] 2018 dollars) for EVM-2 to $190 million (FY 2022 dollars) to account for inflation, with no change in purchasing power,
• Contributions are limited to one-third of the total investigation, and
• The inclusion of a “NOAA [National Oceanic and Atmospheric Administration] Operational Enhancement Opportunity.”⁴

Plans for the most recent EV-I—EVI-6—also show significant changes.⁵ The EVI-6 cost cap ($37 million, FY 2024 dollars) is about the same as the EVI-5 cost cap ($35 million, FY 2022 dollars) for the same Class D payload. In addition, the EVI-6 AO provides the possibility of an additional request of up to $5.3 million for a science enhancement option. The EVI-5 AO, however, included an option for a Class C payload implemented with a cost cap of $108 million in FY 2022 dollars. In contrast, the EVI-6 AO is only soliciting investigations proposing instruments or CubeSats in the Class D payload risk classification.6 According to NASA, this reduction, which is anticipated to be temporary, was made for budgetary reasons.⁷ As detailed in Chapter 2, EVM-2 (GeoCarb) has had substantial cost overruns. In preparation for potential future missions that face cost overruns, NASA ESD could develop a formal mechanism for assessing what aspects of such missions are viable within the mission’s cost constraint and whether funding external to SMD is available to complete the mission despite the overruns.

An additional change of note is that EVI-6 allows for NOAA participation in the form of an operational enhancement opportunity for the instrument selected by NASA, if the instrument’s observables are consistent with NOAA’s operational goals. NASA may explore the ability of flying the (to be) selected EVI-6 instrument on the Joint Polar Satellite System-4. NASA plans to select a Class D instrument and/or Class D CubeSat investigation based on funding availability at the time of selection.

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mittee defined a science target as, “a set of science objectives related by a common space-based observable.” The steering committee defined the observable associated with each science target as a targeted observable. The decadal survey identified five “Designated Observables” that were of the highest priority for implementation by NASA during the survey interval: Aerosols; Clouds, Convection, and Precipitation (CCP); Mass Change; Surface Biology and Geology; Surface Deformation and Change. NASA later announced that it planned to implement the Aerosol and CCP Designated Observables in a single mission.

⁴ See “NOAA Operational Enhancement Opportunity,” on p. 18 in NASA, 2020, “Earth Venture Mission – 3,” NNH21ZDA002O, https://nspires.nasaprs.com.

⁵ NASA, “EVI-6 Acquisition Homepage,” https://essp.larc.nasa.gov/EVI-6.

⁶ A complete list of the major changes between EVI-5 and EVI-6 is available at NASA, https://essp.larc.nasa.gov/EVI-6/pdf_files/EVI6_MajorChanges10142021.pdf.

⁷ Sandra Cauffman, personal communication.

FINDING 3.1: NASA’s interactions with NOAA in the EVM-3 mission appear to be beneficial to both agencies. Following NASA’s selection of future EV missions, it may also be advantageous to allow mission enhancement opportunities relevant to other agencies.

FINDING 3.2: The greatly reduced budget for Earth Venture Instrument 6 (EVI-6) appears to be a direct consequence of GeoCarb’s significant cost overruns. This has a significant negative impact on the range and extent of the science that can be proposed. The science return of future EV missions, the benefits of a regular and predictable cadence for EV selection, as well as the ability of potential principal investigators to keep their teams together if attempting a second (or further) proposal, are threatened when previously selected missions are allowed to grow substantially beyond their planned cost cap.

RECOMMENDATION 3.2: NASA’s Earth Science Division (ESD) should not deviate from the foundational principles of the Earth Venture (EV) program. In particular, the ESD should establish and implement an effective process to strictly enforcing the cost caps established for EV missions.

CHANGING SATELLITE PLATFORMS AND LAUNCH OPPORTUNITIES

The past decade has witnessed a decided change in the availability of launch resources for space access. The success of SpaceX and a number of other recent private industry startups targeting the small satellite market has dramatically changed access to low Earth orbit (LEO) by reducing cost, increasing competition, and providing a broadening set of launch capabilities. A similar evolution is occurring with respect to satellite platform options. The miniaturization of instrument components and sensors has reduced launch weight and size, spurring their use on SmallSats and CubeSats, and leading to lower mission costs. Launching of trains or constellations of these smaller satellites is now becoming possible at the comparable cost of a traditional single large satellite bus. All of these developments bode well for EV-class missions targeted to LEO, with the caveat that space for hosted payloads on the International Space Station (ISS), which served as a platform for EV-I, is in high demand, and opportunities for future hosting will cease toward the end of the decade as ISS is prepared for deorbit around 2031.⁸

In contrast to the last decade’s increasing opportunities for access to LEO, access to geosynchronous Earth orbit (GEO) has become problematic for EV missions, with far fewer than anticipated hosting and launch opportunities. EVI-1, TEMPO, selected in 2012, was planned for insertion in GEO aboard a commercial satellite. It is now in storage with a launch planned for 2023. EVM-2, GeoCarb, is still in development, but it will also need an appropriate host satellite when ready for deployment. EVI-5, GLIMR, selected in October 2019 and planned for launch in 2026-2027, also requires access to GEO. NASA did not anticipate that GEO access would become a stumbling block for EV missions. An obvious concern, particularly for EV-I missions, is the potential scientific loss that would result should community members unsure of NASA’s ability to secure hosting opportunities be discouraged from making the significant investments in time and resources that are necessary to mount a successful EV proposal.

The trend toward smaller, lighter, less expensive satellite platforms and instruments would seem like a win-win to both the developers and NASA. Recent EV-I program actions are consistent with this notion, as more recent awardees (EVI-3 TROPICS, EVI-4 PREFIRE, and the presumed EVI-6 mission) are CubeSat-based. While broadening of launch options results in opportunities for the EV-I program, it also prompts additional stresses. Both TROPICS and PREFIRE, for instance, achieve their science objectives through constellations of spacecraft in more than one orbit plane, necessitating dedicated launch services rather

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⁸ Mike Wall, SPACE.com, 2022, “NASA Plans a Fiery End for the International Space Station by 2031,” Scientific American, February 3, https://www.scientificamerican.com/article/nasa-plans-a-fiery-end-for-the-international-space-station-by-2031.

than opportunistic launches when spare capacity is available with other missions. TROPICS requires three launches to deploy six CubeSats, while PREFIRE requires two launches to deliver one CubeSat each.

NASA’s Launch Services Program (LSP) can provide the Science Mission Directorate (SMD) with launch options and cost brackets based on expected mass and volumes during the EV selection process. LSP, however, views its role as a service to SMD and is not involved in AO evaluation or selection. LSP engages missions as requested, but not before critical design review when instrument details and schedules are sufficiently well known to negotiate launch contracts. Because of this, it is not clear how risk is assessed by the selection committee when proposed launch services are significantly different from NASA LSP experience. As such, the committee is concerned that an EV proposal that makes use of non-NASA-provided launch services risks being penalized in the evaluation process.

FINDING 3.3: TROPICS and PREFIRE are examples of EV instrument selections that blur the lines between EV-I and EV-M. Both provide the instrument and the bus (CubeSats), and both need dedicated launchers because of their specific orbit requirements. In addition, the diminished prospects for hosting opportunities to geostationary orbits, and the anticipated loss of the ISS as a host platform after 2031, suggest this blurring of project elements is likely to persist.

RECOMMENDATION 3.3: In future Earth Venture (EV) announcements of opportunity (AOs), NASA should consider discontinuing the distinction between EV Mission (EV-M) and EV Instrument proposals. NASA would then solicit proposals that provide the full mission architecture as is currently done with EV-M. The AO should list any specific hosting or launch opportunity that NASA offers to provide. EV teams would have the option to incorporate these opportunities in their proposals, accounting for their cost to ensure a level competition against proposals that do not take advantage of such NASA-provided accommodation(s).

BENEFITS OF EVOLVING INSTRUMENT TECHNOLOGIES

NASA’s Earth Observing System (EOS) consists of a science segment, a data system, and a space segment made up of a series of polar-orbiting and mid-inclination satellites for long-term monitoring of the Earth as an integrated system, including observations of the land surface, biosphere, atmosphere, cryosphere, and oceans.⁹ Initially conceived in the mid- to late-1980s, missions were developed and launched beginning in the 1990s as a series of large multi-instrument “flagship” missions and smaller focused satellites, often in partnership with instruments and sometimes spacecraft from other nations.

As initially planned, the launch of EOS flagships—Terra (in 1999), Aqua (in 2002), and Aura (in 2004)—each of which was designed to have an expected mission life of at least 5 years, were to be repeated three times in order to generate a continuous record of 15 years or more. However, budget cutbacks to the program, combined with the high cost of the flagships, made this strategy unsustainable. NASA subsequently canceled plans for repeat flights of the flagships and restructured the program in the late 1990s to early 2000s to consist of the original flagships and a suite of smaller spacecraft, each carrying a limited number of research instruments.

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⁹ M.D. King and S. Platnick, 2018, “The Earth Observing System (EOS),” pp. 7-26 in Comprehensive Remote Sensing, https://doi.org/10.1016/b978-0-12-409548-9.10312-4. Also see “Perspectives on EOS,” The Earth Observer, Special Edition, https://eospso.nasa.gov/sites/default/files/eo_pdfs/Perspectives_EOS.pdf, and NASA, 1993, Earth Observing System (EOS) Reference Handbook (G. Asrar and D.J. Dokken. eds.), Washington, DC: NASA Earth Science Support Office, Document Resource Facility, http://www.ciesin.org/docs/005-089/005-089art2.html.

EOS was intended to address a broad range of scientific issues in the Earth sciences; however, the rescoping and restructuring activities of the 1990s moved the program toward a more focused set of objectives.¹⁰ The Earth System Science Pathfinder (ESSP) Program was an outgrowth of the EOS restructuring and, as noted earlier in this report, EV missions were initiated in 2009 within ESSP to further facilitate development and demonstration of new science measurements and new technologically advanced instruments with smaller size, weight, and power, flying on smaller platforms.

An established program facilitating technology innovation is key to the development of these new capabilities. All of the selected EV-I and EV-M utilize instruments based on newer technology. More than 90 percent of the selected instruments have Earth Science and Technology Office (ESTO) heritage, with technology development enabling maturation to technology readiness level 6 maturation (TRL-6). Numerous EV-selected PIs have worked with ESTO on technology development grants. ESTO technology investments have been incorporated in all EV-I and EV-M selected to date except for PREFIRE (EVI-4).

Advanced technology enablers in the EV program have allowed the development of small, but capable radiometers, spectrometers, polarimeters, lidars, and radars. ESTO advanced technology developments are included in 11 of 12 EV-I and EV-M selections.

• Radiometers
  • Thermal infrared (TIR) radiometer—ECOSTRESS (EVI-2). This Class C instrument is deployed on the ISS and measures targeted surface (vegetation) temperatures. It weighs 490 kg and uses 516 W of electrical power. The prototype was developed in an ESTO Instrument Incubator Program (IIP)-10 program as the PHyTIR instrument demonstration.
  • Miniaturized microwave radiometer—TROPICS (EVI-3). These Class D instruments will fly on six dual-spinning 3U CubeSats¹¹ and will carry scanning 12-channel microwave radiometers in three separate orbital planes to monitor tropical weather systems with unprecedented temporal frequency. A qualification unit has launched as a CubeSat demonstrator. The miniaturized subsystems were all developed under the Advanced Component Technologies Program (ACT-10) and infused into CubeSat demonstrations (MiRaTA and MicroMAS, 2017 launches) as a precursor for TROPICS.
  • Hyperspectral radiometer–GLIMR (EVI-5). This hyperspectral ocean color radiometer will measure the reflectance of sunlight from optically complex coastal waters in narrow wavebands from GEO. This instrument has heritage from the GEO-CAPE mission and ESTO investments in IIP and ACT that enabled the maturity of the instruments and technologies for this measurement.
• Spectrometers
  • Ultraviolet/visible (UV/VIS) spectrometer—TEMPO (EVI-1). This instrument will use a GEO host satellite to monitor tropospheric emissions. It is a Class C instrument, and the heritage instrument demonstration was accomplished on an ESTO IIP-10 program. The GeoTASO airborne demonstrator provided the basis for the TEMPO mission data calibration and processing tools and techniques.
  • Grating spectrometer—GeoCarb (EVM-2). This is a Class D instrument that features a 4-channel, slit-scan spectrometer to measure absorption spectra at wavelengths 1.61, 2.06, and 2.32 μm in sunlight reflected from the land to retrieve total atmosphere-column amounts of carbon

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¹⁰ National Research Council, 1999, Assessment of NASA’s Plans for Post-2002 Earth Observing Missions: Letter Report, Washington, DC: National Academy Press, https://doi.org/10.17226/12265.

¹¹ CubeSats come in various sizes. The size is described in terms of units (U), where each unit is 10 cm × 10 cm × 10 cm. Possible sizes are 1U, 2U, 3U, and 6U.

• • monoxide, carbon dioxide, and methane from geostationary orbit. It weighs 156 kg and uses 400 W of electrical power. ESTO spectrometer investments helped in the instrument development.
  • Hyperspectral imaging spectrometer—EMIT (EVI-4). This is a Class C instrument with a hyperspectral instrument (Dyson’s spectrometer) that will fly aboard the ISS. It will measure the different wavelengths of light reflected by minerals on the surface of deserts and other dust sources to determine their composition. This instrument is based in part on the NASA’s moon mineralogy mapper instrument aboard the Chandrayaan-1 spacecraft. It has heritage from the snow and water imaging spectrometer that was developed as part of the NASA IIP-13 project and from JPL airborne spectrometers, particularly AVIRIS (Airborne Visible and Infrared Imaging Spectrometer) and AVIRIS-NG (next-generation). The Dyson imaging spectrometer helped inform the design of the EMIT instrument.
  • TIR spectrometer—PREFIRE (EVI-4). This is a Class D instrument to be flown on two CubeSat satellites in polar orbits sampling Arctic and Antarctic surfaces and clouds. PREFIRE will fly miniaturized TIR spectrometers covering spectral resolution 0-45 μm at 0.84 μm. The sensors are based on technology previously flown on the Mars Climate Sounder, an instrument on the NASA Mars Reconnaissance Orbiter.
• Lidar
  • Lidar—GEDI (EVI-2). This is a Class D payload deployed on the ISS. It features three yttrium-aluminum-garnet (YAG) lasers operating at 1064 nm, collecting information on vertical distribution of vegetation. The initial YAG laser of the type used by GEDI was developed in a Small Business Innovation Research project and early 2000s ESTO IIP.
• Radar and Radiometer
  • Miniaturized microwave radar/radiometer—INCUS (EVM-3). This is a Class C instrument and a technology infusion for RainCube, which was enabled by pulse compression digital radar (Ka Band) and deployable mesh antenna technology, which was a miniaturization initiative at NASA JPL and followed by ESTO’s In-Space Validation of Earth Science Technologies award to demonstrate this measurement from space. The TEMPEST-D radiometer (5 channels from 89-182 GHz) is also a technology maturation from the VENTURE TECH portfolio managed by ESTO. This instrument flew on a 6U CubeSat deployed from ISS, and it demonstrated millimeter-wave radiometer technologies on a low cost, short-development schedule.
• Other techniques
  • GPS reflectometry—CYGNSS (EVM-1). This instrument includes 8 microsatellites that use reflected GPS signals to measure surface winds and air-sea interactions. It is a Class D instrument with a mass of 29 kg and has heritage from an early 2000 ESTO airborne demonstration.
  • Spectro polarimetric camera—MAIA (EVI-3). This is a Class C instrument and is awaiting launch. It is designed to combine multispectral, polarimetric, and multiangular capabilities into a single, integrated imaging system. It has a push broom camera mounted on a two-axis gimbal. Its measurements will cover spectral bands in the UV, visible and near-infrared, and shortwave infrared). It will be more sensitive to aerosol particle properties than the Multi-angle Imaging SpectroRadiometer (MISR), an instrument on Terra that is still operational, and which only covered the visible and near-infrared bands. The design and the technology used in MAIA was supported by an ESD award for its Instrument Incubator Program as the Airborne Multi-angle Spectro Polarimetric Imager-2 (AirMSPI-2) instrument.

PARALLEL EFFORTS

The EV program was envisioned by NASA to consist of science-driven, competitively selected, low-cost missions that would advance Earth system science. However, the NASA EV program does not operate in a vacuum. With more small, cost-effective missions possible, additional agencies, as well as the commercial sector, will be launching an increasing number of small Earth observing satellites. In developing EV solicitations, the committee encourages NASA to clarify the role of the increasing availability of third-party data on surface monitoring, weather, and climate prediction.