Space Sunday: Mars visions, gateways and James Webb

Elon Musk has bold plans for building a permanent human presence on Mars. Credit: SpaceX

The 68th International Astronautical Congress (IAC) ran from September 25th to September 29th, 2017 in Adelaide, Australia, and brought forth a plethora of announcements, presentations and updates from all those involved in space exploration.

one of the more attention-grabbing announcements came – unsurprisingly – from Elon Musk and SpaceX. Already leading the way in private sector launches and launch vehicle reusability,  SpaceX has in many respects set the bar for the launch industry as a whole. Musk, meanwhile has raised eyebrows with his longer-term goals, which focus on human missions to Mars and – eventually – the colonisation of the Red Planet. At the September 2016 IAC, he laid the outlines for achieving these goals, and in 2017 he returned to the IAC to offer further updates and insights to the SpaceX approach.

Most surprisingly, given the company’s reliance on it for revenue generation, Musk indicated that he is prepared to phase out all Falcon 9 launch operations, including the yet-to-fly Falcon Heavy, at some point in the near future in order to focus the company on the development and operation of its Interplanetary Transport System (ITS), which Musk still likes to refer to as the BFR (for “Big F***ing Rocket” on account of its overwhelming size).

The updates ITS launcher, seen here in comparison to the Falcon 9 and Falcon Heavy, will be 106 metres tall, powered by 31 first stage engines (down from the original 42), and capable of lifting 150 tonnes to low Earth orbit. Credit: SpaceX

Fabrication of parts of the first ITS launcher – which is the linchpin for Musk’s Mars ambitions – has been in progress for some time, and SpaceX hope to start on the assembly of the first vehicle in the series in mid-to-late 2018. Musk is now so confident in the vehicle’s development status, he is hoping to have two of the launch vehicles ready to fly cargo missions to Mars during the 2022 launch opportunity – although he emphasised this time frame is “aspirational” rather than a fixed deadline.

This version of the ITS will be slightly scaled-down from the version announced last year, reducing the overall launch height and mass of the vehicle, and the number of main engines it will require – 31 instead of 42. The 2022 mission will have a two-fold purpose: deliver core components required for human operations on Mars to the surface of the planet; located subsurface water / water ice which could be extracted and used to generate oxygen which could be used within the atmosphere of a future base, and as an oxidizer in fuel used by vehicles making the return flight to Earth.

The upper stage of the ITS is an interplanetary craft powered by a mix of methane (CH4) and oxygen (both of which can be manufactured on Mars, allowing the craft to be re-fuelled there for return flights to Earth) and carrying either cargo in its upper section, or up to 100 passengers in 40 cabins and common crew spaces which offer living space in excess of the space found in an Airbus A380 airliner. Credit: SpaceX

According to Musk, should this mission proceed to plan, it will be followed in 2024 by four craft carrying a mix of equipment, supplies and crews to Mars to commence human exploration of the planet.

All of this is highly ambitious, technically and financially. On the technical front, there are significant issues to be addressed, most notably – but not limited to – that of the radiation threat posed by Galactic Cosmic Rays (GCRs). As I’ve pointed out in past Space Sunday articles on this subject, solar radiation – often seen as “the” radiation threat – can be managed relatively well, simply because it is generally low-energy radiation.

The ITS upper stage on the pad at Musk’s future Mars colony and awaiting refuelling / a return to Earth. Credit: SpaceX

GCRs, however, are high-energy particles which are much harder to deal with: and there is a lot of them in interplanetary space to deal with. Data from the Mars Science Laboratory’s flight to Mars in 2012 revealed that an unprotected astronaut on a similar flight would face the equivalent radiation dose as having a full-body CAT scan every 5-6 days for six months – definitely not a healthy proposition. There are technologies  being developed which can mitigate GCRs, such as such as hydrogenated boron nitride nanotubes (BNNTs), but these are still some way from being available for general use in spacecraft and spacesuit designs. Musk didn’t expand on how SpaceX plan to handle things like GCRs.

He was, however, more forthcoming on how SpaceX would finance the construction and operation of the ITS system. firstly, SpaceX will build up a “stock” of Falcon 9 units which could be used (and re-used) as launchers and components for Falcon Heavy launchers. Secondly, and once available, the revised ITS will be offered as a commercial launch vehicle capable of placing 100 tonnes into low Earth orbit and delivering objects to geostationary orbit or the moon; payloads could be single large items or multiple items. The plan is to use the stock of Falcon boosters through until customers have confidence in the ITS launcher (which will also be reusable) in order to switch over to using it, after which, all Falcon operations will be phased out.

Musk plans to offer the ITS for launches to LEO, the space station, geostationary orbit and even to the Moon for cargo flights, etc. Shown here, an ITS upper stage with solar panels deployed, releases a large single payload into LEO. Credit: SpaceX

In addition, and with usual Musk showmanship, the entrepreneur indicated further revenue could be obtained by offering sub-orbital aerospace flights between major cities in record time. According to his calculations, he claimed that such flights could ferry customers between Bangkok and Dubai in just 27 minutes, or between Tokyo and Delhi in 30 minutes, using a smaller variant of the ITS.

Quite how these system would work or how the necessary support infrastructure needed to support launch / recovery / refurbishment operations around the globe would be financed was not made clear – nor was the potential cost of tickets.

Lockheed Martin’s Mars Base Camp

SpaceX isn’t the only private company aiming to put humans on Mars. Also at the 68th IAC, Lockheed Martin announced a significant update to their Mars Base Camp vision first put forward at the 67th IAC in 2016. However, where SpaceX plans for a direct-to-Mars capability which can be utilised for other space operations, Lockheed Martin are attempting to add flesh to the bones of NASA’s nebulous plans for reaching Mars using dedicated, single-purpose hardware. They also indicate they expect NASA should be the lead organisation in this efforts.

As such, the concept will make use of NASA’s Space Launch System in the launch and assembly of the Earth-Mars transport, which would utilised Orion vehicles, station station-style habitat modules and yet-to-be defined technologies ostensibly developed under NASA’s NextSTEP research programme.  In short, it will require a number of SLS launches from Earth to cis-lunar space where, at the Deep Space Gateway (see below), they will be assembled into a massive,  interplanetary space vehicle. This will utilise two Orion craft, one as the main command and control vehicle, the other to manage excursions to the Martian captive moons, Phobos and Deimos.

The Lockheed Martin Mars Base Camp interplanetary craft and the “laboratory module” sent to permanent Mars orbit ahead of the mission. Credit: Lockheed Market.

Originally, all this expenditure would have seen the mission merely place a crew in orbit around Mars; actual landings would only be made by some unspecified means at an unspecified point in the future. However, at the IAC in September 2017, Lockheed Martin extended the basic Mars Base Camp concept to add a single stage lander capable of multiple flights between Mars orbit and the surface of Mars, carrying crews of six and the supplies and equipment needed for surface says of 2-3 weeks at a time, the vehicle acting as their base camp.

This craft, which would use Orion avionics and command and control systems, will be sent to Mars ahead of the crewed interplanetary ship, where it would remain docked with the laboratory module sent ahead of the main mission, awaiting the arrival of assorted crews.

The Lockheed Market Mars lander vehicle, added to the company’s Mars Base Camp concept at the 68th IAC. Credit: Lockheed Martin

While it may be built on “existing technologies”, Mars Base Camp still suffers from the drawbacks of much of NASA’s long-term thinking: justifying the use of the Moon / cis-lunar space, rather than focusing on actually getting to Mars and establishing a presence there.

Cis-lunar space is cited as a necessary  “stepping stone” for mission further afield. However, it can be argued that there is little practical benefit to be gained from using it to reach places like Mars. Construction-wise, we are already familiar with assembling complex structures in Earth orbit, and the benefits of launching missions from cis-lunar space are almost entirely negated by the need to get there in the first place. Add to that the fact there are precious few technologies for a Mars mission that cannot be more effectively tested in cis-lunar space (or indeed in lunar orbit or on the surface of the Moon) than the can be from Earth orbit, and the position of those who see using it as a “stepping stone” as a distraction, rather than necessity, can be understood.

Deep Space Gateway

First announced by NASA in the spring 2017, the Deep Space Gateway – mentioned above – is intended to be a space station in cis-lunar space (actually operating in a near-rectilinear halo orbit) serving as a “gateway” for the human exploration of the solar system.

Other than requiring four SLS launches between 2021 and 2026 to develop it, full details of the Gateway programme have been hazy since the announcement (like much of NASA’s long-term thinking – something the agency has been criticised for by both the US Congress and the Government Accountability Office (GAO). However, at the 2017 IAC one thing did become clear: the Deep Space Gateway will likely be a joint US / Russian effort.

The Deep Space Gateway being assembled as it passes the Moon. Occupying a Halo orbit around an Earth-Moon Lagrange point, the facility would range between 1,500 and 70,000 km from the Moon. Credit: Boeing.

The Russian news agency TASS broke the story that Roscosmos, the Russian space agency will be supplying between one and three of the Gateway’s core module units, possibly flown atop one of the proposed heavy launch variants of the Angara rocket.

How this will affect the overall configuration of the Gateway is unclear; NASA has already solicited proposals from various aerospace contractors for the development of the Power Module and Habitation System which were intended to be the major elements of the  original Gateway. Some are now speculating that Russia’s involvement could see the facility turn into more of a “mini-ISS”, a space station serving a range of scientific endeavours rather than being solely focused on acting as a “stepping stone” to the rest of the solar system.

This latter idea could make the Gateway a far more logical programme than has so far been suggested. Halo orbits in the Lagrange regions in the Earth-Moon system offer some significant benefits for science and space observations (the latter can be seen on a much larger scale with the James Webb Space Telescope, which will operate close to one of the Lagrange points in the Sun-Earth system).

Besides the Russians, the Canadian Space Agency has indicated an interest in being a part of the Gateway programme, proposing they supply a solar sail for the station. This could be used to re-orient the station as required using the solar wind, massively reducing the amounts of hazardous hydrazine fuel the station would require and which would need to be routinely delivered to it.

James Webb Delayed

NASA’s ambitious James Webb Space Telescope (JWST) – in many respects perhaps the most exciting astronomical science mission to take place since the launch of the Hubble Space Telescope – has suffered a slight setback.

Originally scheduled for launch in October 2018,  the mission will now not get off the ground until some time between March and June 2019. The delay is not due to any technical or hardware concerns or issues. Rather, it is because the integration of the various spacecraft elements is taking longer than expected.

The James Webb Space Telescope. Credit: NASA

Although deemed as a part of NASA’s Next Generation Space Telescope programme, JWST is in fact a joint endeavour between the US Space Agency, the European Space Agency and the Canadian Space Agency. Under the terms of the programme, NASA – as prime developer of the telescope – was required to complete a launch preparedness review of the telescope one year ahead of the planned launch period – the launch being the responsibility of the European Space Agency.

This review was completed in September 2017, and revealed that several elements of the final integration of some key components is taking longer than anticipated. One example of this is the installation of more than 100 sun shield membrane release devices. These are absolutely vital to the mission, as they allow the telescope’s layered sun shield to be deployed to protect the on-board instruments from the heat of the Sun.

Until the announcement, made on September 28th, NASA has been insistent that integration and testing of the complex telescope had been proceeding on schedule  – and that there was time in-hand which could be used to deal with some delays. In fact, on September 27th, a day before the announcement was made, the US agency had indicated JWST was still on course for an October 2018 launch.

JWST deployment. Credit: NASA GSFC / Clampin

Once integration and testing of the telescope has been completed, it will be prepared for launch and shipped to the Guiana Space Centre in Kourou, French Guiana, where it will be integrated with a European Ariane 5 launch vehicle, which will boost it on its way to the Earth-Sun L2 (Lagrange) point, approximately 1.5 million km (930,000 mi) beyond the Earth. Once there, deploying slowly while en route, it will occupy a halo orbit and have a primary mission lifetime of 5 years, although it is hoped it will operate for around 10. Unlike HST, it will be operating far beyond reach of any repair  / upgrade missions, and hasn’t been designed for in-space maintenance.

During its mission, JWST will carry out a huge range of space science and observations, a part of which will involve peering at far-off exoplanets in an attempt to use its on-board instruments to detect any bio-signatures lurking in their atmospheres which might hint that they host living, breathing organisms. Thanks to programmes such as the Kepler Observatory and studies of potential exoplanet locations from Earth, there is already an extensive science mission outlined for JWST, which include a good look at systems such as TRAPPIST-1 with its seven Earth-sized worlds, and Proxima b.

Following launch, JWST will take about a month to reach its science orbit, and will then commence a 6-month period of check-out and adjustment before the main science mission commences.