Space Sunday: Samples from Mars & catching a rocket in mid-air

NASA-ESA Mars Sample Return mission elements: the Mars 2020 rover (l) responsible for collecting / caches samples; the Sample Fetch Rover (2028) responsible for collecting the sample tubes and delivering them to (r) the SRL-1 lander (2028), part of the system for delivering the samples to orbit and the Earth Return Orbiter (MRO – 2027), seen overhead (Earth shown in a piece of artistic licence to illustrate the idea of a sample-return mission). Credit: NASA / ESA

NASA’s Mars 2020 rover Perseverance is busy on Mars carrying out a range of science duties, including gathering samples of sub-surface materials that can be sealed in tubes and returned to Earth by a future Mars Sample Return (MSR) mission.

In all, the rover has 43 such sample tubes, and the plan is for it to “geocache” them at one or two locations on Mars at some point, with one of the caches being used as the target for the MSR mission, which NASA had, until recently, vaguely pointed towards being some time in the 2030s.

However, MSR has been prioritised both by the Decadal Study (see: Space Sunday: Future Mission, SpaceX Update) and US politicians – and as a result NASA and ESA have dusted down plans first put forward in 2018/2019 and revised them for a proposed joint, three-part (and frankly overly-complicated), six vehicle mission. This comprises:

  • The Sample Retrieval Lander 1 (SRL1) – carrying the Mars Ascent Vehicle (MAV) – NASA.
  • The Sample Retrieval Lander 2 (SRL 2) – NASA – carrying the Sample Fetch Rover (SFR) – ESA.
  • The Earth Return Orbiter (ERO) – ESA – – carrying the Earth Entry Vehicle (EEV) NASA/ESA.
An early concept of the MSR mission. Credit: NASA/ESA

The mission plan is complicated, but will currently run like this:

2027: The ESA-built ERO vehicle is launched to Mars via an Ariane 6 rocket. It uses ion drive propulsion to cruise to Mars, arriving in 2028, where it will use a separate propulsion system to ease itself into the correct orbit.

2028: SRL-1 and SRL-2 launch to Mars on faster transfer orbits.

  • These both make a soft-landing relatively close to the sample cache.
  • SRL-2 deploys the SFR, which drives to the sample cache and retrieves sample tubes. It then drives the tube to SRL-1.
  • SRL-1 uses a robot arm to transfer the tubes to a capsule at the forward end of the MAV (stowed horizontally on the top of SRL-1 in a protective tube).
  • When ready, the MAV and its protective tube are raised to a vertical position. A spring-loaded “catapult” will then eject the rocket from the tube at a rate of 5 metres per second, allowing the rocket’s motor to safely ignite and power it up to orbit to rendezvous with MRO.
A drawing indicating the major components of the Sample Fetch Rover (SFR). Credit: ESA

The sample return capsule is then transferred from the MAV to a NASA-built containment system contained in the EEV attached to MRO. The latter then engages its ion drive to start it on a gentle transfer flight back to Earth, which it will pass in 2032/33. As it approaches Earth, the EEV is ejected and enters the atmosphere to make a passive descent and landing (no parachutes), using shock absorbing materials to cushion its touch-down in Utah.

Work has already commenced on elements of the mission – such as the Sample Fetch Rover, which ESA is building, and uses design elements  – such as the flexible wheels, the camera systems, etc., – used in the ExoMars Rosalind Franklin rover, and I’ll have more on this joint mission as it develops.

Rocket Lab Grab Their Rocket Out of the Air

Rocket Lab, the New Zealand / US commercial launch company, has recovered one of its launch vehicles after it had successfully sent its payload on its way to orbit. But unlike other companies developing / using re-useable rocket stages, Rocket Lab didn’t land their rocket or let it splashdown – they snatched it out of mid-air with a helicopter!

Rocket Lab’s Sikorsky S-92, trailing the capture line, circles on May 2nd (UTC), awaiting the descent of an Electron rocket first stage under a parachute. Credit: Rocket Lab

The two-stage Electron rocket lifted-off from Rocket Lab’s launch pad on New Zealand’s Mahia Peninsula at 22:49 UTC on May 2nd. The mission, called There and Back Again, was Rocket Lab’s 26th Electron flight, and after sending the upper stage and its payload of 34 smallsats on their way to a successful deployment on orbit, the rocket’s first stage started back to Earth, deploying a parachute to slow its descent.

At just under 2 km above the Pacific Ocean of New Zealand’s coast, Rocket’ Lab’s recovery Sikorsky S-92 made a successful rendezvous the the rocket’s first stage and made an initial capture using a line slung below the helo. Unfortunately, the helo’s crew were forced to release the line within seconds due to the way the booster started to behave after being caught. The rocket then continued one to a splashdown, and was recovered by the Rocket Lab recovery vessel, which was also on station for this eventuality.

Left: the cockpit view as the helicopter approaches the descending Electron first stage. Right: Moments before the capture line initially snags the lines of the rocket’s parachute lines. Credit: Rocket Lab

Whilst not 100% successful, the attempt demonstrated Rocket Lab are on the right track, and likely will be able to capture future Electron stages in mid-air (thus avoiding exposing them to saltwater on splashdown), and fly them back to base for re-use.

In Brief

Virgin Galactic Delays Passenger Sub-Orbital Flights Until 2023

On May 5th, 2022, Virgin Galactic announced it is postponing the start of commercial services with its SpaceShipTwo suborbital spaceplane from late 2022 to early 2023, citing supply chain and labour issues.

Both VSS Unity, the first of the operational Virgin Galactic spaceplanes and the MSS Eve carrier / launch aircraft have been hit by extended delivery times of “high performance metallics” used in some of their components, resulting in a shortage of spares and replacement units.

The first flight of Unity with fare-paying passengers had been expected to take place in the 4th quarter of 2022, but has now been pushed back until the start of 2023, with the end of 2022 now earmarked for final flight tests of both Unity and Eve once the supply chain issues have been resolved, ahead of final certification for commercial flight operations.

Virgin Galactic has pushed back the start of its sub-orbital, fare-paying passenger flights to early 2023

The second sub-orbital vehicle, VSS Imagine, the first f the company’s SpaceShip III class, has yet to complete its own test regime, but is also expected to start passenger flight operations later in 2023. It’s not clear how many vehicle of the class will be built, as the company recently announced it plans to introduce a new “delta class” spaceplane in the mid-2020s.

The company also stated it has now sold 800 tickets for sub-orbital flights that will enable customers to experience around 3 minutes of microgravity. The majority of these were at the “introductory” prices of $250,000, but at least 100 have been at the “full” price of $450,000 – although it is believed most customers have thus far only made the basic down payment of $150,000 a ticket.

ESA Indicate Rosalind Franklin Unlikely to Launch Before 2028

The European Space Agency (ESA) has stated that Rosalind Franklin, the agency’s Mars rover and surface contingent of the ExoMars programme is unlikely not launch until 2028.

As I’ve noted in that past, this rover programme is already around 20 years old, and has had more than its fair share of setbacks. It had been expected to head to Mars later in 2022 using a Russian launch vehicle and lander craft. However, Russia’s invasion of Ukraine put paid to that as all cooperative space activities and projects between Europe and Russia were initially suspended and then scrapped – with ESA noting it has no intention of working in partnership with Russia in the future.

While alternate launch vehicles are available that could get the rover to Mars, the ending of ESA-Roscosmos cooperation means Rosalind Franklin is currently without a lander vehicle and, realistically, one cannot be designed, built and tested in time for launch sooner than the 2028 opportunity (the optimal times to launch missions on a cost-effective basis to Mars using chemical rockets occur once every 26 months).

However, even a 2028 launch is questionable. Firstly, the new lander will require a specific type of rocket motor to slow it during the final stage of landing – and these would have to be supplied by the United States, which will require negotiation and agreement. Secondly, the rover now needs new RHUs (radioisotope heating units) that keep it warm both during the trip to Mars and when on the surface. These were originally supplied by Russia, but have now been withdrawn, so ESA must again turn to the United States for new units. The RHU situation means that ExoMars can only launch from US soil, and this, with the need for the US-built motors likely means the land should be built in the US, all of which needs to be negotiated, so ESA can’t simply go out and build a lander for itself.

Europe’s ExoMars rover Rosalind Franklin – more delays. Credit: ESA

Also, a 2028 launch would mean that the rover would arrive in its designated landing / science location just one month ahead of the annual dust storms that sweep through the region, something to could adversely impact getting the rover checked-out and commissioned after it arrives. A longer flight time could be employed, but orbital mechanics dictate that the rover would be stuck in interplanetary space for two years before arriving at Mars – which is also far from ideal.

Nor is that all. The 2028 launch opportunity has been prioritised for the revised ESA/NASA Mars Sample Return (MSR) mission (see above). As such, there have been suggestions that the entire ExoMars rover could be re-purposed to fulfil the role of the ESA rover in that mission – although it is not clear how this would impact the rover’s current design and its own science goals.

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