Space Sunday: rocket power and space stations

Dude, why’s my car in orbit? Musk’s cherry-red Tesla photographed from its payload mounting on the Falcon Heavy upper stage. Credit: SpaceX

On Tuesday, February 6th, SpaceX launched one of the world’s most powerful launch vehicles – in fact, currently, the most powerful launcher in operation since NASA’s massive Saturn V rocket by a factor of 2 in terms of lift capability.

I’m of course talking about the Falcon Heavy, which after years of development and launch delays, finally took the to skies at 15:45 EST (20:45 UTC) on the 6th, after upper altitude wind shear delayed the launch from its planned 13:30 EST lift-off time – which would have been at the start of the four-hour launch window required to send its payload on a trans-Mars injection heliocentric orbit.

Three cores, 27 Merlin engines, 5 million pounds of thrust. A remarkable shot of the lower part of the Falcon Heavy at lift-off, captured by Ryan Chylinski. Credit: R. Chylinski / SpaceFlight Insider

The run-up to the launch was handled fairly conservatively by SpaceX: Falcon Heavy is a complex system – effectively three individual Falcon 9 rockets which have to operate in unison. So much might go wrong that even Elon Musk was stating he’d be happy if the vehicle was lost after it had cleared the launch pad. This was not a joke: in September 2016, a pre-flight test of a Falcon 9 lead to the loss of the vehicle, its payload and massive damage to its Cape Canaveral launch pad, putting a dent in SpaceX’s launch capabilities at the time. A similar event at Kennedy Space Centre’s pad 39-A, the only launch facility capable of handling the Falcon Heavy, would be a massive setback for the company’s 2018 aspirations.

However, and as we all know, the launch proved to be flawless. All 27 engines fired as required, generating the same thrust as 18 747 running all their engines at full throttle, and the vehicle took to the air. Two minutes later, the “stack” reached the point of “max-Q”, the point at which aerodynamic stress on a vehicle in atmospheric flight is maximised (symbolised in a formula as “q” – hence “max Q”). At this point, were the rocket’s engines to continue to run at full thrust, the combined stresses could literally shake the vehicle apart; so instead the motors are throttled back, easing the strain on the vehicle, prior to them returning to full thrust as “max-Q” has passed.

The Falcon Heavy flight path. Credit: SpaceX

After passing through “max-Q”, the vehicle completed perhaps the most spectacular part of its flight. Their job done, the two outer Falcon 9 stages shut down their engines and separated from the core rocket. Then then re-lit their engines to boost them vertically to where both could perform a back-flip and then return for a landing at Cape Canaveral Air Force Station, just south of Kennedy Space Centre. So perfect was this aerial ballet that the two boosters landed almost simultaneously.

The central first stage should have also made a return to Earth after separating from the upper stage, landing aboard one of the company’s two autonomous spaceport drone ship (ASDS) – necessary because the stage had flown too far and too high to make a return to dry land. This was the only point of failure for the flight. Unfortunately, it over-burnt its propellants, leaving it without enough fuel to land on the floating platform. Instead, it slammed into the sea at an estimated 480 km/h (300 mph), some 100 metres (300ft) from the ASDS – the only notable failure in the launch.

Two from one: the moment at which two Falcon 9 cores are about to touch-down at Cape Canaveral Air Force Station following the February 6th, 2018 launch of Falcon Heavy. Credit: SpaceX

The second stage, however, performed perfectly, the payload fairings jettisoned, and the world got its first look at a car in space: Musk’s own Tesla Roadster, complete with a spacesuited mannequin (“Starman”) at the wheel, Don’t Panic – a reference to The Hitch Hiker’s Guide to the Galaxy – displayed on the dashboard. During the ascent, he was apparently listening to David Bowie’s Space Oddity played on the car’s stereo.

Right now, “Starman” and the car are en-route to a point out just beyond the orbit of Mars. It is is on a heliocentric (Sun-centred)  orbit, travelling between 147 million and 260 million km (91.3 million and 161.5 million mi) from the Sun, and passing across both the orbits of Mars and Earth in the process – but without actually coming close to either. It will continue in this orbit for millions of years.

A telescope at the Tenagra Observatory in Arizona captures the Tesla Roadster moving across the backdrop of the stars on Thursday, February 8th, 2018. Gianluca Masi (Virtual Telescope Project)/Michael Schwartz (Tenegra Observatory)

The launch was largely lauded around the world – with the live stream broadcast becoming the second most-watched event in YouTube’s history, gaining 2.3 million concurrent views (the largest audience for a streamed event was the 2012 the Red Bull Stratos jump, which racked in 8 million concurrent views). It’s an event unlikely to be repeated until the first flight of NASA’s own Space Launch System rocket due in 2019 and – and some point down the road – SpaceX’s own massive Interplanetary Transport System launch vehicle.

The Saturn V, still the world’s most powerful rocket to enter operational flight status, and Falcon Heavy compared. The NASA Space Launch System will have a greater thrust capability than either, but initially will only be able to place around 70 tonnes into low Earth orbit (LEO) and around 28,000 kg into a trans-Lunar injection (TLI) flight to the Moon

With the launch came some changes in SpaceX’s plans for the Falcon Heavy.

The second launch for the vehicle had been slated to be a Saudi Arabian communications satellite. This now appears to have been moved to a Falcon 9 launch, leaving the next Falcon Heavy flight, scheduled for June 2018, to be a military launch designed to assess its suitability for such launches under the US Air Force’s Evolved Expendable Launch Vehicle programme – which until recently was the exclusive purview of United Launch Alliance.

SpaceX has also stated that they will no longer use the Falcon Heavy for crewed launches, as had been originally planned. This will instead be left to their next launch system, the Interplanetary Transportation System, colloquially referred to as the BFR – or Big F***ing Rocket.

As a part of its design, BFR includes a massive 46 metre (160 ft) long space vehicle capable of carrying dozens of people into space. It’s a core part of the company’s goal to send humans to Mars, and the company appear so confident about its development track they no longer see the point in going through the necessary certification process to allow Falcon Heavy to launch human crews into space.

This change of focus means that the plans to send two tourists on a trip around the Moon aboard a Dragon 2 capsule launched by a Falcon Heavy in 2019 have now been scrapped, with a SpaceX spokesperson suggesting the flight would go ahead at some point, but using the BFR.

Falcon Heavy Maiden Flight Trivia

  • As well as the Tesla roadster, the maiden flight included a plaque carrying the names of the roughly 6,000 people employed at SpaceX.
  • Also aboard the car is a small disk of quartz crystal roughly 2.5 cm (1 inch) across. Called Arch (but pronounced “ark”) , meaning “archive”. It forms a “library” of data on human civilisation. Developed by the Arch Mission Foundation, it is part of a plan to “seed” the solar system with libraries of information on humanity.
  • While the Tesla car is in keeping with SpaceX’s record of launching unusual payloads on the first flight of their vehicles, it was only decided to use it after NASA had turned down the opportunity to fly a science payload  – at SpaceX’s expense  – on the rocket. The alleged reason the offer was turned down is that some at NASA view the Falcon Heavy as “competition” for their Space Launch System.

Europe’s ExoMars Trace Gas Orbiter Approaches Final Orbit

Trace Gas Orbiter (TGO) is the first major element of the European Space Agency’s (ESA) ExoMars mission. It arrived in Mars orbit in October 2016. At the same time, ESA attempted to place a small lander – carried to Mars by TGO – on the surface of the Red Planet. That attempt failed (see here and here for more), but TGO continued.

Since March 2017, TGO has been engaged in a series of aerobraking manoeuvres, using the tenuous Martian atmosphere to gradually lower and circularise its orbit for an initial and highly elliptical one extending to some 33,200 km (20,750 mi) out from the planet. In February 2018, ESA announced that these manoeuvres had successfully reduced that orbit to a much smaller one, extending a mere 2,700 km (1677 mi) from the planet while maintaining its closest approach to Mars at some 110km (69 mi) above the planet’s surface.

Visualisation of the ExoMars mission’s Trace Gas Orbiter conducting aerobraking manoeuvres to March of 2018. Credit: ESA

Aerobraking avoids the need to carry big engines – which in turn need a lot of heavy propellants – in order to achieve a desired orbit. However, it’s no easy matter. Both the atmosphere and gravity of Mars vary in density and strength respectively across its surface. Thus aerobraking becomes a delicate balance between variable atmospheric drag, fluctuating gravitational attraction and careful management of velocity.

Over the next few weeks, TGO’s motors, small though they are, will be used to gradually nudge the craft from its current orbit (shown in red, above) into its final circular orbit (shown in green). Once established in that orbit, the primary phase of the science mission – a deep examination of Mars’ surface, characterising the  distribution of water and chemicals beneath the surface, studying the planet’s geological evolution, identifying future landing sites, and to searching for possible bio-signatures of past Martian life – will start in earnest.

In spring 2021, TGO is expected to be joined at Mars by the second phase of the ExoMars mission – a lander and rover vehicle. Scheduled for launch in July 2020, the lander and rover will conduct a wide range of static and mobile studies of the surface, sub-surface and atmospheric environments within their landing site – a site to be selected with the help of TGO’s findings. In particular, the rover will be looking for the bio-signatures for past or current Martian microbes.

US to End ISS Operations by 2025?

As the Trump administration prepares to release a fiscal year 2019 budget proposal, fears have been raised that one of the things it may call for is an end to funding for the International Space Station by 2025 three years ahead of the expected time ISS operations might end.

The International Space Station, circa 2007. Credit: NAS

Just how successful the ISS has been is a matter of debate; while a stunning feat of space engineering, much of what has been achieved aboard it has come at the expense of bolder space endeavours, and potentially could have been achieved more cost-effectively through other means. However, it is there and has been built at huge expense, and so the idea of killing it when it still has perhaps another two decades of operational life left in it, has been seen by some as a ludicrous idea. Among them is Republican Senator Ted Cruz, chairman of the space subcommittee of the Senate Commerce Committee, who has stated he hopes the reports that the ISS funding is to be drawn to a close by 2025 are, “as unfounded as Bigfoot,” and stated his determination to see the space station continue through to at least the currently planned 2028 end date.

He is joined in this view by both Democrats and other Republicans – and by many in the private sector, whom the White House would like to see take over an US human presence in low Earth orbit. While keen to do so, companies such as Boeing also want more of a transitional period between operating the internationally funded ISS and in providing the means to continue near-Earth orbital activities using their own facilities built with government support.

Is the drive to develop the DSG behind the rumours concerning bringing the ISS – which could in theory operate through to the late 2030 and is currently supposed to be funded through until 2028 – to an end in 2025? Credit: NASA

A particular worry for many is that an early retirement of the ISS would, for the United States, lead to a situation akin to the ending of the space shuttle programme in 2011. That move has left America without the means to launch crews into orbit directly from their own soil (and will not be able to do so operationally until 2019). The fear with the ISS is that if the Deep Space Gateway (DSG) project is delayed, it might leave the United States with any orbital facilities, be they in LEO or an extended halo orbit around the Moon.

One of the benefits seen in ending US involvement in the ISS is it would free funds for the DSG. However, some have pointed out there’s a certain double irony in this. Firstly, many of the goals outlined for the DSG are pretty much the same as given for the ISS (e.g. science, and providing an outpost for reaching out into the solar system) – so why burn money on the DSG when the ISS could do much of what’s required?

The second point raised is that the shuttle and the space station were supposed to become a gateway to the solar system. Instead, they became a means to justify one another: the space station was needed to give the shuttle something to do / somewhere to go, the shuttle was needed to take crews to and from the space station; a budgetary loop that effectively left NASA unable to do anything else in terms of human space exploration for over thirty years. There are fears that ultimately, the Orion crewed vehicle and the DSG might end up in a similar fiscal loop, the DSG existing purely to give Orion somewhere to go, and Orion existing just to get crews to / from the DSG, with the costs effectively starving NASA of the budgetary support it needs to engage in other human space endeavours.

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5 thoughts on “Space Sunday: rocket power and space stations

  1. The Falcon Heavy launch was one of the most exciting things I’ve ever watched live. An amazing achievement. I’ll never forget the sight of the two booster rockets landing so perfectly together.

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    1. I’ve been fortunate to attend several shuttle launches (most notably the maiden flight of the Endeavour, when we were guests of NASA at KSC). all were thrilling, but I have to confess the Falcon Heavy flight was just stunning. As you say, seeing the two outer Falcon 9 booster land in almost perfect unison was simply stunning. My only regret is that due to visitors, I was unable to join the Sansar folk who had gathered at the Apollo Museum to witness the event together.

      SpaceX comes in for a lot of flak (and this launch being no exception – Kevin MeKenna writing in the UK’s The Guardian for example, utterly missed the significance of the launch, demonstrating an almost tragic understanding of the benefits space flight has had on our understanding of the very environment he claims we should be taking care of instead of throwing rockets into space “for the benefit of millionaires”) but the fact remains, they are setting the pace in launch vehicle evolution and capabilities. As such, those who scoff at the company’s aim to build and launch the BFR might want to take a little care – they could find themselves eating their own words some time in the next decade …

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      1. I haven’t seen MeKenna’s article – I’ll look it up tomorrow – but I’m broadly familiar with this argument and whilst I want to disagree with it (because I love what SpaceX – and, more broadly, all of Musk’s companies –
        are doing), I’m aware I should probably pay it more attention precisely *because* I want to disagree with it. Obama’s big decision to open up space flight to private companies is now starting to show its return in these astonishing achievements, but I will admit that it gives me an itch I want to scratch. Most of us are pretty certain that Musk only has humanity’s wellbeing at heart, but arguments about these principles should not be shaped by the personality of one man. What if SpaceX was owned by someone like Trump?

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        1. “What if SpaceX was owned by someone like Trump?” – well, part of McKenna’s view – that it’s about millionaires playing with big toys because they can – would potentially be true (I say that in semi-joke, but there is probably an underlying truth in it, self-aggrandisement and all that). Elon Musk is very much a horse of a different colour. He’s been an advocate of human missions to Mars for almost 2 decades. For example, he was involved with the Mars Society, an organisation that (for a time) revolutionised thinking on how to send humans to Mars and bring them back, in the early 2000s. So yes, his vision is very much leaning towards humanity’s long-term benefit and growth.

          I’m not sure I’d entirely agree with Obama deciding “to open space flight to private companies” – that was already happening pre-Obama. SpaceX, for example, was already developing launch systems well ahead of Obama’s space policy shifts. They’d already funded the Falcon 1 entirely privately, and were working on the Falcon 9 as a result of NASA initiating the Commercial Orbital Transportation Services (COTS) programme in 2006, designed to allow private companies in the US to bid for contracts to fly uncrewed resupply missions to the ISS. Similarly, changes to US laws under the remit of the Federal Aviation Authority (FAA), the body actually responsible for granting launch licences, etc., had been made in 2005 in order to broaden private enterprise space tourism (sub-orbital to orbital)

          Where Obama did play a role was in the decision (after something of a protracted period of re-evaluation) to remove crewed flights to the ISS using Orion, and opening the doors to private enterprise to bid for this work. That allowed Boeing, SpaceX, Blue Origin and Sierra Nevada Corporation (the four finalists) to kick-start development of crew-capable vehicles to fly to / from the ISS, and which could also be operated in private launch activities. The primary aim of this was to free-up development of Orion as a command and control element / crew recovery vehicle for operations which could take humans further into the solar system.

          Whether the latter actually comes to pass remains to be seen. I personally am in the camp with the worry that for all the talk of lunar missions and the Deep Space Gateway, all we’re actually going to see is an almost 50-year period when humans went no further than low Earth orbit to a possibly decades where we go no further than the Moon unless someone like Musk and SpaceX can make missions to Mars a reality via the private path. And even then, and purely as a layperson in these matters, I’m not entirely sure SpaceX’s BFR heavyweight approach is really the right was to go and for multiple reasons. For example, landing a tonne of payload on Mars is massively tricky (and currently the upper limit of our capabilities), but SpaceX is now focused on trying to land up to 100 times that amount per mission when, in reality, there is no actual need to go so massive.

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