Space Sunday: future missions, SpaceX update

Decadal Survey 2023-2032. Credit: NASEM

A study outlining priorities in US planetary science for the next decade was published by the United States National Research Council (NRC) on April 19th. Entitled Origins, Worlds, and Life: A Decadal Strategy for Planetary Science and Astrobiology 2023-2032, the report is part of a 20-year history of the NRC offering periodic roadmaps for America’s space exploration strategies, during which time many of the recommendations made have gone on to shape NASA’s activities and goals.

The next decade of planetary science and astrobiology holds tremendous promise. New research will expand our understanding of our solar system’s origins, how planets form and evolve, under what conditions life can survive, and where to find potentially habitable environments in our solar system and beyond.

– from the introduction of the 2023-2032 Decadal Survey

The report – running to 522 pages – includes input from science organisations, universities and research institutions from around the world. Within it, the committee has identified twelve priority science questions that should be the focus of NASA and America’s work in space. These are divided into three categories: Origins, Worlds and Processes, and Life & Habitability, with each category including a total of 12 major areas of investigation, with the committee outlining the robotic and crewed mission proposals that NASA should consider undertaking in support of these investigations.

This report sets out an ambitious but practicable vision for advancing the frontiers of planetary science, astrobiology, and planetary defence in the next decade. This recommended portfolio of missions, high-priority research activities, and technology development will produce transformative advances in human knowledge and understanding about the origin and evolution of the solar system, and of life and the habitability of other bodies beyond Earth

– from the 2023-2032 the Decadal Survey

Highlights of the survey’s recommendations include:

Flagship Missions

Flagship missions are the “big ticket” missions for NASA. At the time of the last Decadal Survey (2011), the flagship missions were identified at the Mars 2020 mission, Europa Clipper, and the Uranus Orbiter and Probe (UOP) – the latter ultimately losing out to the other two.

This being the case, UOP has been awarded the highest priority within the 2023-32 survey. It would deliver an in-situ atmospheric probe into Uranus’ atmosphere and conduct a multi-year orbital tour to study the ice giant and its system of moons, with the objectives including the study of Uranus’ interior, atmosphere, magnetosphere, satellites, and rings.

A drawing of the proposed Uranus Orbiter and Probe.

Due to the need to utilise planetary fly-bys (gravity assists) to reach its destination, UOP would not launch until the early 2030s, when planetary alignments would facilitate the needed assists, with the primary science mission around Uranus commencing in the mid-2040s.

A second Flagship mission identified by the survey as worthy of consideration by NASA is the Enceladus Orbilander. If funded, this mission would launch in the late 2030’s sending a compact robot vehicle to orbit Saturn’s icy moon of Enceladus, passing through the plumes of water we know to be escaping the moon’s subsurface ocean as a result of gravitational interactions with Saturn. The aim of the mission is to to sample and study the plumes before making a landing on Enceladus in the early 2050s to search for biosignatures either in the surface ice.

New Frontier Missions

Regarded as “medium priority” missions, the New Frontier missions identified in the survey for further / continued development are designed to increase our understanding of the major and minor bodies in the solar system. The cost of such missions is capped at US $1.65 billion, with NASA likely to select two new missions from the crop of recommendations. They comprise:

  • Europa Clipper: a former Flagship mission, now downgraded to reflect its advanced status, this is due for launch in October 2024. It will arrive in orbit around Jupiter where it will fly by Europa multiple times, investigating the moon’s habitability and help identify a potential landing site for a future Europa Lander mission.
  • A Ceres sample / return mission to follow-up on the Dawn mission’s orbital survey of the asteroid Ceres.
  • A comet sample return mission.
  • A network of lunar landers to collect geophysical data.
  • A Saturn orbiter mission to follow-up on the Cassini mission.
  • The Oceanus Titan orbiter, proposed but not selected as a 2017 Frontiers Mission.
  • A Venus “in situ atmospheric” mission – possibly a vehicle to deliver a balloon that would drift through the upper reaches of Venus’ atmosphere.
  • A Triton (Saturn’s largest moon) orbital mission.

Mars Exploration

For the first time, a Decadal Survey identifies Mars as a dedicated target for exploration, specifically  underling two missions:

  • The long-planned Mars Sample Return mission, which has had its share of ups and downs, and has yet to be properly settled upon by NASA.
  • The yet-to-be-defined Mars Life Explorer (MLE) mission designed to look specifically for signs of current microbial life on Mars and to pave the way for future human missions to Mars.
[A] sample return will provide geologic materials that are not represented among Martian meteorites and whose volatile, organic, and secondary mineral composition have not been altered by impact… In addition, sample return will allow for future analyses by instruments and techniques not yet developed. As has been the case with the Apollo samples from the Moon, future analyses are expected to yield profound results for many decades after sample return.

– from the 2023-2032 the Decadal Survey

The survey calls for cohesion between robotic and human missions is a priority for future missions to the Moon and Mars. Credit: NASEM

Lunar and Human Exploration

Unsurprisingly, the survey supports NASA’s lunar ambitions, identifying the need for robotic missions in support of a human presence on the Moon, the establishment of an “Artemis Basecamp” in the south polar region of the Moon. This also recommends much more coordination for human activities on the Moon to be linked with human missions to Mars.

Planetary Defence

A call for the development and improvement of our abilities to detect and track near-Earth Objects (NEOs) that may come to pose an impact threat for Earth, and the means to mitigate such genuine threats when identified and confirmed.

The highest priority planetary defence demonstration mission to follow DART and NEO Surveyor should be a rapid-response, flyby reconnaissance mission targeted to a challenging NEO, representative of the population of objects posing the highest probability of a destructive Earth impact (~50-to-100 m in diameter). Such a mission should assess the capabilities and limitations of flyby characterization methods to better prepare for a short-warning-time NEO threat.

– from the 2023-2032 the Decadal Survey

Which of the missions outlined by the survey are actually adopted will be down to a combination of NASA planning and congressional funding / willingness to support the goals and aspirations set out throughout the report.

Picture of the Week

Paris, April 17th 2022: the full Moon rises in line with the Arc de Triomphe and the Avenue des Champs-Elysées – a single exposure image captured by astro-photographer Thierry Legault. No compositing or other post-process used. Credit: Thierry Legault

SpaceX Starship Update

SpaceX has been moving ahead rapidly with the development of both prototypes of their Starship / Super Heavy vehicles and the facilities required to manufacture and launch them.  Here’s a quick summary of key activities since my last update:

  • Booster 7 (sans any Raptor 2 engines) has undergone initial cryogenic and pressure testing whilst on both the orbital launch platform and the “Can Crusher”.
  • The test on the launch stand marked the first time any Super Heavy booster has had both tanks filled with cryogenic liquid (in this case, liquid nitrogen).
  • The tests on the “Can Crusher” have comprised both an ambient nitrogen pressure test of the tanks under high gaseous pressures and liquid nitrogen load tests.
  • The load tests have apparently included the use of the thrust rams of the “Can Crusher”, designed to simulate the pressure exerted against the rocket as a result of the thrust from its Raptor 2 motors.
Booster 7 undergoing cryogenic testing using liquid nitrogen to fill both tanks to capacity, forming frost on the outside of the stainless steel hull. Credit: NASA Spaceflight.com

At the same time as this work has been carried out, work on the next Super Heavy rocket – Booster 8 – appears to have been accelerated.

  • This has led to a degree of speculation that Booster 8 will actually make the first orbital launch attempt, not booster 7, which may be consigned to the role of a structural test article (much like Booster 1 and Booster 4).
  • The reason for this thinking is that Elon Musk has stated that with Raptor 2 production still ramping up, there will only be sufficient engines for a single booster by May, when SpaceX hope to complete the first orbital launch test. So if these engines are to be used on Booster 7, there seems little need to accelerate the assembly of Booster 8.

It also now seems likely that Starship 24 will be the vehicle to participate in the orbital launch attempt with either Booster 7 or 8. Originally, the inclusion of a payload bay door to facilitate the deployment of Starlink satellites, had been thought of as indicative that Ship 24 would be held over until SpaceX is ready to commence testing Starlink deployments with Starship.

Animated showing how the payload slot on Ship 24 and Ship 25 could release multiple Starlink satellites. Credit: OweBL

However, Ship 25 has also now been fitted with a similar mechanism, suggesting that it will be a feature of Starship vehicle during at least the next phase of development. If so, it would fit with the idea that SpaceX would like to demonstrate Starship’s ability to deliver payloads to orbit as soon as possible, even if other aspects of the system are still in development.

Nor is this the end of progress over recent weeks:

  • The SpaceX launch faculties at Kennedy Space Centre’s Pad 39A have seen the foundations for the new Starship / Super Heavy launch facilities start to come together.
  • At Roberts Road just a few kilometres away, the sections of the massive orbital launch tower are being assembled in parallel, with each section additionally being outfitted with all the required plumbing, ducting, etc., it requires.
  • This means that when ready, it should be possible for SpaceX to rollout, secure, stack and connect the sections into a finished tower in relatively short order compared to the construction of the tower at Boca Chica, which was erected in stages and the plumbing added after initial construction was completed.
From early April: four sections of the Starship / Super Heavy launch support tower under construction at Robert Road, Kennedy Space Centre (KSC). When complete, this section will be moved to the launch facilitates under construction within Pad 39A at KSC. Credit: Julia Bergeron / NASA Spaceflight.com
  • Also at Robert’s Road, work on the new fabrication and assembly facilities for Super Heavy boosters and Starship vehicles is moving forward.
  • All of this progress has perhaps been why SpaceX appear to have abandoned – or at least delayed – the development of a second orbital launch facility at Boca Chica (although this might also be in order to head-off any negative findings by the FAA on those plans when the latter’s environmental study and recommendation is finally published).
  • one of the two oil rigs SpaceX purchased for offshore launches has also completed the first stage of refurbishment – the removal of all equipment and elements not required for its use as a floating launch platform – and has been relocated in preparation for more extensive fitting-out to commence.

There is a long way to go before the Starship / Super Heavy system proves itself – from being able to launch successfully through to the routine and safe recovery of both boosters and starship vehicles to demonstrating the system is safe for human flight, let alone routinely flying with crews / passengers or being ready to meet the company’s long-term goal of reach Mars (a very different proposition to launch / landing here on Earth). However, there can be no denying the determination of SpaceX to develop, iterate and expand along their development path.