ASAP on board with NASA’s DSG as stepping stone to Mars

by Chris Bergin

NASA’s major push towards building a new outpost near the Moon has received encouraging words from its key safety advisory body. NASA’s Aerospace Safety Advisory Panel (ASAP) was told the build up of the outpost in the 2020s represented an ambitious, forward-looking and credible plan that has both agency and political support.

DSG:

NASA has been realigning its exploration plan to involve a Deep Space Gateway (DSG) over recent months, somewhat moving priority away from sending crews out to explore Near Earth Asteroids (NEA) which has only received lukewarm interest from NASA’s political paymasters.

This “interim” step in the overall exploration roadmap will involve a number of the 2020s missions involving NASA’s new heavy-lift launch rocket, the Space Launch System (SLS).

SLS still needs to conduct its test flights, which are going to receive officially realigned launch dates in the coming weeks following the decision not to modify Exploration Mission -1 (EM-1) to a crewed flight.

Although the opening two missions have returned to their previous plan, the dates are still going to later than originally advertised, with a NET (No Earlier Than) August 2019 for EM-1 and June 2022 for EM-2 on the current internal schedule.

The large gap between the opening two missions is unavoidable per NASA direction, with EM-1 launching on the Block 1 SLS, before major changes – especially to the Mobile Launcher (ML) – are conducted for the larger Block 1B SLS.

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The Block 1B, however, will be NASA’s HLV workhorse, providing an upmass capability not seen since the Saturn V days. It will also be capable of an array of missions thanks to its powerful Exploration Upper Stage (EUS).

Providing her with missions that utilize the power of the rocket, while also progressing on the stepping stones towards Mars missions, has resulted in numerous studies that have changed numerous times.

The latest, and fast becoming a favored approach from both within NASA and political circles involves the DSG. This plan is a partial throwback to the L2 Gateway that gained interest at NASA in 2011.

Its first major public overview of the new plan came via the NASA Advisory Council (NAC), where Bill Gerstenmaier, Associate Administrator for NASA’s Human Exploration and Operations Mission Directorate (HEOMD), presented the NAC with the agency’s Deep Space Gateway and Transport Plan.

This phased approach ties in current NASA exploration goals, which includes the wealth of knowledge being gained into long-duration human space flight on the International Space Station (ISS).

“At the very top level, NASA’s plan involves using the ISS now, operating near the Moon in the 2020s, and then leaving the Earth-Moon system and reaching Mars orbit after 2030,” noted the ASAP minutes from the body’s latest meeting.

“The more detailed plan contains four different phases. Phase 0 involves continuing research and testing on ISS to solve exploration challenges, evaluating the potential for the use of lunar resources, and developing standards.”

Advancing the work already conducted, NASA will leverage its own goals with commercial partnerships, with NASA expected to publish individual documents for each system, such as environmental control and life support, power, data, storage, etc., that would contain voluntary standards rather than requirements, with the hope that both international and industry partners would be able to develop hardware and software that could easily be incorporated into the overall architecture, per the overview to the ASAP.

Phase 1 will take place in the 2020s, when NASA undertakes missions to cislunar space for construction efforts of the DSG. By this time commercial partners will be onboard, providing elements of the DSG to be launched on SLS missions. The stock in Cislunar has risen over recent years, with the United Launch Alliance (ULA) – and others – working on large-scale plans to commercialize this region of space.

“In terms of basic functionality, the DSG is being planned to support multiple NASA, commercial, and international objectives,” added the overview. “It would be designed for the deep space environment and would support a crew of 4 for total mission durations of up to 42 days with the Orion vehicle attached.

“It would include a power and propulsion bus and a habitat, and would incorporate a logistics strategy that could involve cargo resupply or crew transportation flights by industry or international partners, such as what is done now for the ISS.”

However, it would not be of the size nor complexity of the ISS, with an intent to “keep it simple”. The entire DSG could be launched on three SLS Block 1B missions over three years, according to the latest overview.

Phase 2 will see the construction of the Deep Space Transport (DST) and its subsequent shakedown and verification.

“Phase 1 marks the beginning of missions in cislunar space, including building the DSG and initiating assembly of the Deep Space Transport (DST),” added the minutes. “Phase 2 involves completion of the DST and conduct of a year-long, Mars-simulation mission – sometimes called a ‘shakedown cruise’ – in 2029.”

This is where the DSG effort directly benefits missions to Mars, with this stepping stone providing the tools to naturally progress to the major challenge of sending humans to the Red Planet.

The DST element of the DSG will have Mars in mind, potentially be used for the human missions to the vicinity of Mars – such as the touted Mars flyby mission – and could be a hybrid system with chemical propulsion for Mars gravity-well capture and departure, and SEP (Solar Electric Power) for the rest, per the overview to the ASAP.

“This would potentially eliminate the need for a pre-deployed propulsion system at Mars for crew return. The DST would be designed for 3 Mars-class missions of about 1000 days each with a crew of 4, launched on a single SLS Block 1B vehicle. The thinking is that it could be refueled, resupplied, and have at least a minimal outfitting performed in cislunar space.”

Phases 3 and 4 would involve the beginning of sustained crew expeditions to the Martian system and to the surface of Mars, with a mission to Mars orbit in 2033.

The usually conservative ASAP noted that while it encouraged NASA to start doing more detailed planning for exploration related launches post EM-2, seeing that now – with the kind of system design and engineering trade studies that are being conducted – was pleasing.

“The Panel acknowledged a lot of progress (has been made) and believes NASA is on the right track. (And that) while the timelines on some of this may seem lengthy, when one considers all of the technical challenges that need to be addressed and the constraints on resources, NASA appears to have a very credible plan going forward.”

(Images: NASA and L2 artist Nathan Koga – The full gallery of Nathan’s (SpaceX Dragon to MCT, SLS, Commercial Crew and more) L2 images can be *found here*))

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