by Duncan Lunan

All the way up to October 7^th, ESA continued launch preparations for the Hera mission to the asteroids Didymos and Dimorphos  (Fig. 1), the latter hit by the DART asteroid deflection experiment in 2022.  Hera was scheduled to launch on a SpaceX Falcon 9 booster, and already in place within the payload fairing  (Figs. 2, 3 & 4), but Falcon 9s had been grounded after a fault with the re-entry of the second stage on a previous mission. 

The spent booster entered atmosphere and burned out over the Pacific, to avoid adding to the space debris problem, but it wasn’t where it was supposed to be, presumably because the deorbit burn was misaligned.  In the end the Federal Aviation Authority cleared the one-off launch because the second stage was going to take the probe out into solar orbit, rather than returning to Earth  (Fig. 5).  It would be fair to say that the media on the day were more preoccupied with the implications of that concession than they were with the actual mission.  The first stage wasn’t returned to Earth either, using all its fuel to increase the probe’s velocity, and meaning that both veteran boosters were lost on their 23^rd flights, with that record still to be achieved and passed. 

Hera was launched successfully on October 7^th  (Fig, 6)  despite repeated weather warnings and even an unexpected rainstorm during fuelling.  Although the launch window extended to October 26^th, the priority was to get it off and clear the launch pad before Hurricane Milton moved in  (Fig. 7), possibly requiring the removal of the payload from the pad and protecting the booster as well as can be, as with NASA’s Europa Clipper  (see below).  The storm is expected to generate 180 mph winds, with a 15-foot storm surge, one of whose novel features will be that the batteries of electric cars left behind may explode after immersion in salt water.  It’s recommended that all such cars be made safe by experts after flooding, and as 5 million people are being evacuated, that alone may be a tall order.

Hera’s first target is Mars, and during a gravitational slingshot passing 5000 to 3000 km miles from the planet in March 2025  (Fig. 8), it will pass within 1000 km of Deimos, Mars’s minor moon.  As well as being an important test of the instruments for the asteroid encounters and the subsequent Ramses mission  (see below), the flybys will add significantly to our knowledge of Deimos, which has been rather the poor relation in Mars studies.  It has been photographed by all the Mars orbiters since Mariner 9 in 1971, but usually from a distance, and in ‘Mars (3):  The Moons of Mars’, ON,  August 1^st, 2021, I wrote mostly about Phobos for that reason.  Like most of the moons in the Solar System, Deimos has a trapped rotation, keeping the same face to its planet, and the farside of Deimos was photographed for the first time by the United Arab Emirates’ Hope orbiter in April 2023  (Fig. 9). 

It revealed a somewhat unattractive deep cleft, suggesting that Deimos is a ‘contact binary’, like Comet 67P  (Fig. 10)  and Arrakoth, previously called ‘Ultima Thule’  (Fig. 11), and strongly supporting the idea that Phobos and Deimos are reassembled fragments of a much larger moon which fragmented in the past  (Fig. 12). 

That may have happened several times, with Mars forming rings in each episode from which much of the material fell on to the planet  (Fig. 13), and it may be destined to happen several more times in the future  (Fig. 14).  But the Hope’s infrared scan of Deimos is remarkably even for what should be such a variegated surface, not even showing the cleft  (Fig. 15), so more information is needed.  Now that Hera is on its way, investigations are starting to see whether this can become a synchronised survey by two or more spacecraft – Mars Express, Mars Reconnaissance Orbiter, Mars Odyssey, MAVEN and Trace Gas Observer are all still operational in the current ‘Mars fleet’.

Hera will reach the asteroid pair in October 2026, and on approach it will release two cubesats, Juventas and Milani, to study them in detail and hopefully to land on both  (Figs. 16 & 17). 

Milani is named after the late, Andrea Milani, who first proposed what became the DART mission in the form of a two-spacecraft ESA mission called Don Quixote  (Fig. 18).   Hera is too big to decelerate and will make a flyby through the Didymos system while the cubesats go in close, and the fly-through will be an important precursor for ESA’s next asteroid mission, Rapid Apophis Mission for Space Safety (Ramses), to the notorious Near Earth Object Apophis when it passes close to the Earth in 2029  (Fig. 19).

News reports on Sunday and on Monday morning gave the launch time as 10.52 a.m. Eastern Daylight Time, and as I had other commitments, I had my alarm set for 16.45 BST.  EDT switches back to ET, real time, by the Mean Sun  (see ‘Time by the Stars’, ON, March 27^th 2022)  on the first Sunday of November, five days after BST becomes GMT/UT and the clocks go back.  Confusions are rife during October, and I am not exempt, particularly after sleepless nights like I had on Sunday to Monday for other reasons.  When I switched on NASA TV, which is now called ‘NASA +’, I discovered that the launch had already taken place, but a full repeat was available from liftoff to the middle of the second stage burn.  Having watched that, I switched to Space.com, which was showing the live coverage from SpaceX’s website, and that continued until after the spacecraft separated from the booster  (Fig. 20).  I then switched to ESA TV, which continued to broadcast from mission control at ESOC until after AOS  (Acquisition of Signal)  when contact with Hera was resumed.  Though nobody mentioned it at the time, Hera had already deployed its solar panels, an hour after launch.  Each channel had terminated coverage of the launch when their own part of it was done.

That sequence has an interesting parallel for me.  At one of the IBM Heathrow Conferences which I attended in the 1980s, their head of research and development gave a talk called ‘Can AQ  [Adaptive Quotient]  improve your IQ?’  He started by asking everyone who owned a car to put their hands up.  With an audience of 200 top scientists, university administrators and the like, almost everyone did.  (I was a rare exception, having had to give up my MGB after 9 years in 1983.)  He then said, ‘Keep your hand up if you know the capacity of the engine’, followed by ‘put you hand down if you’ve recently insured or re-insured your car’, then ‘keep it up if you know the ratios of the gearbox’.  After a couple of equally technical questions, only two hands remained, at which he predicted that those would belong to either motoring experts or professional drivers.  Sure enough, one was the motoring correspondent for a major newspaper, and the other was a professional racing driver for a famous manufacturer.  His point was that computer manufacturers were trying to sell home computers with that kind of technical information, when what the customer wanted to know was ‘how will having it change my life?’  It occurred to me that only people like me would have undertaken that chase through the internet for continuing coverage of the Hera launch, and by profession I’m a science writer specialising in astronomy and spaceflight.  I should be grateful that such coverage is available nowadays for the likes of me, by contrast with the years when the BBC would terminate live coverage as soon as the vehicle left the pad.

Meanwhile, the long-awaited launch of the Europa Clipper mission will have to wait a bit longer.  It was originally planned to go on NASA’s Artemis booster, but at $4.1 billion per launch that proved too costly, and the launch was reallocated to SpaceX’s Falcon Heavy, scheduled for October 10^th 2024.  But the approaching threat of Hurricane Milton has kept it confined to the SpaceX hangar at Kennedy Space Centre  (Figs. 21 & 22), secured against high winds and heavy rain which are moving in.  The launch window for Jupiter is open till November 5^th, so it’s to be hoped that by then the storm and its aftermath will be over.  (‘Milton!  Thou should’st not be living by that hour’.)  After arrival in the Jupiter system in 2030, Europa Clipper will make 49 orbits of the planet, to minimise its exposure to the radiation belts, passing Europa every 2-3 weeks at distances down to 16 miles and conducting studies with nine different instruments, looking for conditions which might support life  (Fig. 23).  It’s NASA’s largest deep-space explorer to date, with solar panels 100 feet across and weighing as much as an African elephant.

The similarity between the payload photos of Fig. 4 and Fig. 22, though Fig. 22’s is much larger, recalls the April 1^st 1989 issue of the California Spacefaring Gazette, which alleged that NASA had mistakenly launched the Hubble Space Telescope to Venus in place of the Magellan radar orbiter.  A NASA spokesman was imagined saying, “Well, those payload canisters all look alike, they’ve been in storage for years and the labels have come off… it was a mistake anyone could make, but at least now we’ll get a very close look at Venus…”

Another delay due to weather is the return of the Crew-8 astronauts, who have been on the ISS since March  (Fig. 24), and were to have returned in the Crew-8 capsule Endeavour from which Mathew Dominic photographed the hurricane on October 9^th   (Fig. 25).  The return will not be till October 13^th at the earliest, by which time it’s hoped conditions in the recovery area will have improved.  Last week I was congratulating myself on having sorted out the confusions in the media between ISS expeditions 71 and 72, Crew Dragons 8, 9 and 10  (both spacecraft and people), and Elon Musk’s Ships 4, 5 and 6.  Seemingly SpaceX is taking a leaf from ESA’s book and is preparing the fifth Starship/Superheavy combination for launch on October 13^th, although the Federal Aviation Authority is insisting that it can’t be cleared for flight before the end of November.  What will come of that conflict remains to be seen.

But in concentrating on all of the above, I missed another mix-up, and I haven’t checked back to find out whether the fault was mine or the media’s.  In last week’s article I confused the second launch of the United Launch Alliance’s Vulcan-Centaur booster, with the first launch of the Blue Origin New Glenn booster.  The common factor was that both use Blue Origin’s new methane powered BE-4 rocket engine  (Fig. 26), built to end the United Launch Alliance’s dependence on Russian rocket engines, but also to further Blue Origin’s plans for the Moon, including a lander big enough to build a moonbase for NASA  (Fig. 27).  It was New Glenn which was scheduled to launch NASA’s twin ESCAPADE Mars probes, which have been postponed to a February attempt because the New Glenn is powerful enough to take them on a shorter trajectory.

The intended payload for Vulcan 2 was the maiden flight of the Sierra Space Dream Chaser, a winged lifting body which initially came third in the competition for NASA’s new cargo and crew carriers to the International Space Station.  SpaceX and Boeing won the initial contracts with the Dragon and Starliner spacecraft respectively, but Dream Chaser has made enough progress to gain contracts for seven flights to the ISS.  (Fig. 28;  Dave Adalian, ‘Dream Chaser spaceplane 1st launch delayed until 2025’, EarthSky, online, 7^th July 2024.)  But it had to be dropped from the second certification flight of Vulcan-Centaur because the ULA needs to have it operational for upcoming commitments with the Space Force and the Department of Defence;  hence the launch with a dummy payload which I described last week.

Dream Chaser will be launching into Space Station orbit on its early missions, and as the ISS passes over Cornwall, Sierra Space already has a contract with the Cornwall Spaceport for landings there, as will be required for European missions and for unforeseen contingency landings.  For the moment, Prestwick Spaceport plans have been kicked into touch:  the money allocated to it in the South Ayrshire Growth Plan has been redirected by South Ayrshire Council  (presumably with the agreement of the Scottish Government)  to build an overpass.  No doubt it’s badly needed – the limited funding for the Ayrshire Roads Alliance is a continuing topic at Community Council meetings, for very good reason.  But that’s not necessarily the death-blow for the Prestwick Spaceport that one might think.

As I pointed out in ‘Update on Spaceflight’, ON, 14^th January 2024, Dream Chaser is a glider and will probably have sufficient cross-range capability to land at Prestwick if Cornwall is closed, e.g. by weather, which has always been Prestwick’s strong suit.  NASA’s secret X-37B space plane has already flown one mission passing directly over Prestwick, and ESA’s planned ‘Space Rider’ will be going into near-polar orbit, so it too will need a coastal airstrip with the transport links to be a gateway to Europe for orbital manufacturing experiments and later products.

All of these will be flying uncrewed, although a piloted version of Dream Chaser is in development, as originally intended, and designs for a larger crewed version of Space Rider appear from time to time.  ESA has always seen large-scale space transport as one of its long-term aims.  Just today  (April 11^th), it has been announced that the X-37B’s current seventh mission is going to undertake aerobraking manoeuvres, initially to change orbital height, but with the potential for altering orbital inclinations and landing at a much wider range of sites.  For any of these to use Prestwick there will be no need for the large, not to say grandiose, Prestwick Spaceport terminal which was planned in the mid 2000s  (see ‘Update on Spaceflight’), but some crew handling facilities will be required for piloted missions.  Perhaps for Prestwick Spaceport, getting things started will be a case of ‘If they come, then you can build it’.