Mars orbit-to-surface LLT

The NASA HAT has analysed the feasibility and effectiveness of missions to the moons of Mars (and Mars orbit generally) prior to landing crew on the surface of Mars. One potential advantage of such missions is that orbit-to-surface teleoperations can be conducted with very short communication delays (e.g. under 0.5 s). As illustrated in Fig. 1, this kind of LLT can allow crew members to be highly responsive by virtue of having such a short communications delay with assets on the Mars surface – a form of ‘real-time’ or ‘near real-time’ operations.

Fig. 1.

Low-latency teleoperations from Mars Orbit. Credit: NASA/GSFC.

Such surface assets could either be pre-deployed prior to human missions to Mars or deployed during human Mars orbital missions. Depending on the capabilities of those assets (e.g. mobility and scientific capabilities), it should be possible to scientifically explore somewhat large areas of the surface (perhaps relatively quickly), and potentially the sub-surface, prior to crew landing on the surface. Not only would such advance exploration provide valuable science and mission data, it could also identify previously unknown Special Regions that might be explored thoroughly before a crew lands on the surface. In this way, orbit-to-surface teleoperations can also potentially inform crew landing site selection and areas of special planetary protection concern.

Depending on what we eventually learn about contaminant transport and contamination impacts to Martian sites of interest, a crewed surface landing may compromise planetary protection protocols. Crew operations of surface assets from Mars orbit would avoid this concern – as long as the telerobotic surface assets were properly cleaned and maintained prior to deployment – and perhaps during operations as well. Because important remaining questions are (a) the size of the area (including subsurface) that reconnaissance efforts should cover and (b) the kinds of analyses needed over that area prior to crew landing, LLT could be an invaluable tool for preparations to realize astrobiological and planetary protection objectives.

For example, LLT from orbit to surface would also be useful for precursor sampling of Mars surface locations in advance of human activities. The notion of understanding levels of biological risk and of designating special zones or areas has been mentioned in multiple reports about planetary protection and human missions. For example, the NRC Space Studies Board ‘Safe on Mars’ report (2002) recommended that:

The notion of zones and areas pre-designated as ‘safe’ were discussed further in subsequent reports by NASA and ESA (e.g., NASA 2005; ESA-NASA 2007). Even now, the concept of using pre-designated zones remains important for planetary protection and science considerations. A recent NASA workshop on Planetary Protection & Human Extraterrestrial Missions (2016) noted the importance of zonal approaches (and special regions) in development of procedural requirements for planetary protection during human missions. In particular, workshop participants noted the utility of robotic and LLT assets for gathering important precursor data about natural environments and processes on Mars. Such LLT data-gathering – either from Martian moons or on the surface – could provide important research information in advance of human arrival or science exploration activities on the surface.

Participants at the same NASA workshop identified 25 different knowledge gaps (touched on at the end of this paper) that should be addressed through research and technology development in order to make incremental progress towards formulating NPR for planetary protection during human missions. LLT assets and operations were identified as useful for gathering important data about the natural environmental process on Mars, particularly details about meteorological conditions and dispersion of dusts/aeolian transport that may be associated with dissemination and sterilization of microorganisms. As shown in Fig. 2, while LLT may be useful for gathering precursor data in Special Regions, there remain challenging questions about if and how robotic surface assets may need to be cleaned if they are used for repeat sampling in the same or multiple Special Regions.

Fig. 2.

Multiple special regions low-latency teleoperations from Orbit.

Drilling into the subsurface before landing crew may also turn out to be an important function for LLT. Astrobiology activities and in situ resource utilization (ISRU) present potential planetary protection challenges – e.g. drilling below 5 m may be considered drilling into a Special Region (COSPAR 2002/2011). Conducting LLT drilling from orbit may turn out to be one of the most difficult LLT tasks and very sensitive to time delays, so extremely reliable and low-latency data communication paths will be needed.

The use of force-feedback or haptics (e.g. transmitting a sense of feel/force into the hands of an operator) may turn out to be an important technology development path to ensure effective LLT drilling (including the possibility of hitting subsurface challenges such as certain kinds of rock or other unforeseen subsurface environmentsFootnote ⁶), and space-based haptics tests using the International Space Station are being conducted (Schiele et al. Reference Schiele2016). It may also be the case that humans will ultimately be needed close to the drilling site to help address any number of challenges that may arise – particularly for deep drilling. Drilling is covered in more depth in the next section.

Crew-on-surface and LLT drilling

Much of the data gathering that can be conducted from Mars orbit via LLT could also be performed once the crew has landed on the surface. This would be particularly useful for any scouting that needs to be done immediately after the crew arrives, as well as during a period of acclimation, or later during the mission as well. Such surface LLT has the additional advantage that for many scenarios the latency will be lower and potentially less complicated when surface assets are closer and perhaps in direct line of sight at all or most times.

For example, the HAT Mars Destination Operations Team developed an integrated long-duration 500 day ‘science-driven’ surface operations concept in which LLT was invoked as a possible strategy for exploring new and interesting areas, while the crew is on the Martian surface at a safe distance from presumed or possible Special Regions (Bobskill & Lupisella Reference Bobskill and Lupisella2014). The team reviewed past literature and invited presentations on planetary protection and contamination control. It was suggested that if the surface assets can be maintained to meet planetary protection protocols, then such assets could be teleoperated to safely explore areas around the landing site and beyond. During the period of crew acclimation following their initial landing, LLT can be conducted from the habitat into the surrounding landing area in order to gain an additional detailed understanding of the landing area environment before the crew performs its first EVAs or other operations that may be problematic for contamination reasons.

Even after the crew has landed on the Mars surface, LLT can help address a number of planetary protection and contamination concerns associated with human exploration by providing a relatively clean method to explore areas of biological interest. This would allow the crew to remain isolated from areas that could be biologically dangerous, including areas near the habitat that may need to ‘cleared’ or re-validated for safety or other reasons that may not have been sufficiently addressed before crew arrival. In comparison with other human-associated assets (e.g., habitats, crew transport vehicles, pressurized rovers or EVA suits), robotic assets are easier to clean, re-clean and maintain in a clean state over time. Thus, LLT can be used for robotic operations in sensitive areas, with the potential for robotic cleaning while in sampling areas or when going between potential or known Special Regions if cross-contamination in a concern (as noted in Fig. 2 above).

Based on present characterizations of potential Special Regions on Mars it may be prudent to find and explore such regions telerobotically in order to address contamination control concerns in advance and to mitigate potential biohazards to crew members and possibly to terrestrial biota when crew members return to Earth (COSPAR Planetary Protection Policy 2002/2011; Beaty et al. SR-SAG Report Reference Beaty2006; NRC Space Studies Board 2015). The complexities and uncertainties regarding Special Regions are noteworthy. The 2015 NRC Space Studies Board emphasizes uncertainties by stating:

Depending on how Special Regions are ultimately defined and understood in their actual environments (e.g. through precursor mission data, modelling, etc.), and depending on what kinds of contamination control technologies may be implemented with crew assets (such as suits, rovers, sample acquisition systems, drills, etc.) it may also be prudent to explore these scientifically sensitive regions for long periods of time without humans in the immediate environment of interest. Similarly, if there is sufficient uncertainty about the biological or chemical nature of Mars samples, it may be wise to explore strategies for conducting extensive LLT sample operations as well. Teleoperations may also be important for addressing other concerns related to planetary protection, such as spacesuits and their uses (e.g. cleaning, maintenance, doff-don by the crew, etc.) and ‘end of life’ infrastructure and mission operations.

During surface missions (and possibly before crew lands), there will likely be a need to drill into the subsurface for a number of reasons – ranging from resource prospecting and ISRU, to the search for life and biohazard detection. LLT options would be valuable for various operations involved in drilling into the subsurface, which may have special concerns relevant to planetary protection, Special Regions, and crew-on-surface activities. COSPAR policy (2002/2011) presently indicates that drilling deeper than 5 m is considered to be drilling into Special Regions. Furthermore, astrobiologists have already identified difficult sampling requirements that may someday require materials from 250 to 300 m below the surface [e.g. to obtain samples from an aquifer where there is potential for Mars extant life (MEPAG HEM-SAG Report 2008)]. If such deep-drilling is eventually required, it will be one of the more challenging tasks ahead – making it advisable to keep humans away from the immediate drill zone at different times. Thus, both initially and in the longer term, there are anticipated situations that strongly suggest the utility of LLT.

While drilling for samples using LLT from orbit may be useful prior to crew landing, it is reasonable to think that additional drilling, for science and otherwise, will occur after the crew is on the surface. By its nature, drilling is likely to be a very challenging and long-duration activity. Thus, LLT drilling at a safe but close distance on the surface will have its advantages (e.g. close line of sight communications, visual proximity, better contingency response capability, etc.) Additionally, it will be prudent to conduct drilling without having to put humans in the immediate drill zone, at least initially, if not for longer durations while sensitive drilling activities are being conducted. A HAT drilling report (Rucker et al. Reference Rucker2013) on activities during human missions has indicated a number of other important considerations:

Acknowledging these concerns, the report made further recommendations relevant to LLT:

• • If deep drilling operations must be autonomous and/or telerobotic due to planetary protection concerns, technology development emphasis should be placed on automated core and fluid acquisition and handling, low mass borehole stabilization, rugged and high-temperature sensor development and placement, automated drilling control software, and software testing and validation.’

• • If deep drilling operations must be completely autonomous and/or telerobotic, a high-fidelity mass and operational timeline analysis should be completed to determine whether it makes more sense to perform this activity on a crewed versus robotic mission. Some of this analysis is underway.’

• • Mass should be allocated for automated and/or telerobotic control for deep drilling systems (including power).’

The HAT drilling report also noted the following concerns about drilling:

• • The time-scale for a drill to encounter difficulties is often of the order of 10 to 20 s, making teleoperation from Earth risky. Teleoperation from Mars orbit or Mars surface is feasible, but risks will vary with drill design and drilling conditions, both for shallow and deep drilling.

• • Because ice may be only 3–5 m below the surface within 30° of the equator, it may be advisable to take a conservative approach to shallow drilling. In light of the uncertainties associated with the Martian environment, subsurface planetary protection guidelines will need review, update and mission-specific interpretation.

• • To date, none of the 53 drill technologies surveyed are guaranteed to work for 300 m target depth. In addition, at current demonstrated drilling rates, it may take more than 500 sols to drill to depths of 300 m. Despite these considerations, deep drilling is potentially solvable with technology development, more power, drilling before the crew arrives and possibly LLT drilling.

Surface science lab operations and LLT

A wide variety of science operations and data collection needs may be aided by LLT operations on future Mars missions. For example, the Report on ‘Planning for the Scientific Exploration of Mars by Humans’ (NASA HEM-SAG 2008) noted that Habitat Laboratory requirements for sample analysis should include operations that help to:

• • Facilitate high grading of ‘sample return to Earth’ mass;

• • Enable biology-unique measurements that cannot be done on Earth;

• • Conduct extant life tests (productivity, labelled radio-C, etc.);

• • Monitor environmental isolation (contamination and habitat isolation, curation, etc.); and

• • Use samples analysis data to help direct future sample collections and science decisions.

In addition, the report noted that all operations should be done in ways that ensure separation of Astrobiology experiments from human life sciences biology conducted for the crew (e.g. for crew health).

As shown in Fig. 3, sample handling involves a complex mix of activities, which ultimately involve detailed operations such as sample acquisition, containment, transport & delivery, sub-sampling and subsequent analysis – all of which intersect key considerations relevant to contamination control, planetary protection and crew safety. Even if sampling is planned for areas located outside Special Regions, where crew may do the actual collections directly, there are other considerations involved in ensuring that scientists will have pristine, uncontaminated materials to study – whether on Mars or back on Earth. Not only will real-time telerobotic sample acquisition avoid the threat of introducing terrestrial biota into Special Regions or sample materials, but it will also be beneficial for the science operations as well.

Fig. 3.

The criticality of sample handling.

It is possible that the crew [either operating from orbit or a surface location (e.g., a habitat or rover)], using telerobotic assets on the surface, could efficiently acquire samples, including via shallow and deep drilling and transport them to a pre-deployed science laboratory to classify the samples and conduct additional detailed analysis on the samples as needed. Experiences on Earth with advanced teleoperations technologies such as the da Vinci Surgical System have demonstrated improved remote surgical capability through stabilizing instrument manipulation, enhancing dexterity and allowing for greater precision and operator comfort (Anvari et al. Reference Anvari2005) and should be applicable to more challenging environments such as space and other planetary surfaces.

On Mars, sample analyses done via LLT of laboratory assets would similarly benefit from high-precision manipulators, advanced scientific instruments and operator comfort. As shown in Fig. 4, once the crew has landed, a similar LLT strategy can be used to keep samples relatively isolated from the crew and other surface assets and associated operations by teleoperating a science lab that is some distance from a habitat.

Fig. 4.

Low-latency teleoperations of separate science lab from surface habitat.

In addition to transporting materials to an isolated or remote lab location, LLT could be used to physically manipulate samples, conduct visual sample analysis, prepare samples for molecular analyses using miniature biomolecule sequencers (John et al. Reference John2016), and be safely prepared for rapid, remote response to dynamic science events such as atmospheric or biological phenomena. LLT could also be used to prepare and emplace materials securely into a sample containment unit for launch into Mars orbit and eventual return to earth. Thus, LLT strategy will also help to ensure breaking the chain of contact before returning samples to earth.

Cislunar space

Many LLT science activities, including astrobiology related activities, could be tested on ISS (Fong et al. Reference Fong, Burns and Pratt2014; Thronson et al. Reference Thronson2014) and deeper in cislunar space (Lupisella & Bobskill Reference Lupisella and Bobskill2012; Bobskill et al. Reference Bobskill, Lupisella, Mueller, Sibille, Vangen and Williams-Byrd2015; Lupisella et al. Reference Lupisella, Wright, Bleacher, Young, Gernhardt, Chappell and Beaton2017). For example, work has been done on the mission concept of crew-assisted sample return where crew in the Orion capsule (Burns et al. Reference Burns2013) and/or a cislunar habitat [perhaps at a Libration/Lagrange pointFootnote ⁷ on the far side of the moon in order to have constant visibility of the lunar farside (Lester et al. Reference Lester, Hodges, Ower and Klaus2012)] could acquire a sample and return it to earth. A lunar sample could be obtained by the crew in lunar orbit using LLT to the lunar surface to operate rovers, acquire and analyse samples, and launch them to lunar orbit for pick-up and return to earth. This could help prepare for and test similar systems and operations that might be conducted from Mars orbit.

A Mars sample could also be returned to cislunar space where LLT could be used by the crew in cislunar space to acquire that sample and ensure its containment integrity prior to acquiring it and returning it to Earth. If the proper technology were developed, one or several LLT assets could also be useful to assess the containment integrity and cleanliness of the sample containment unit and to mitigate any potential containment breaches or clean the outside of the sample containment unit to whatever specifications are required. Under all of these scenarios, this ‘in-space’ LLT sample assessment and mitigation strategy could be tested in cislunar space for feed-forward to Mars where crew may acquire collected samples in Mars orbit.

Diversity of LLT assets

A diversity of LLT systems can be used to perform science-related operations in different locations, each with certain advantages and disadvantages. As indicated in Table 1, while many possible LLT platforms and systems can be used to address assorted mission needs, their applicability depends largely on the particular science drivers and operational factors for any given infrastructure and mission construct. Clearly, astrobiology exploration and activities could benefit in various ways from the many candidate assets and options already identified and deemed feasible.

Table 1.

Possible low-latency teleoperations systems and capabilities

End of mission concerns and LLT

In addition to assisting with ongoing mission activities, LLT may also contribute in a number of ways prior to returning to Earth. For example, potential ‘end of mission’ concerns and associated operational details such as disassembly applications or ‘seal up’ operations (e.g. for habitat, rovers, etc.) may be best done via LLT, either while on the surface prior to the crew's launch, or from Mars orbit before leaving the Mars system.

LLT could also be useful in dealing with disposal of the Mars ascent vehicle (MAV) itself, which could be a unique challenge because its uncontrolled impact could release contaminants widely. In addition, LLT of the MAV could help ensure that appropriate end of mission planetary protection requirements are met (e.g. venting down to vacuum to try to kill organisms; transport to, and/or orientation in, a safe in-space location; or possibly a ‘controlled’ landing to a safe zone if needed).