The Week in Space and Physics: Starship and Hakuto

On the inaugural flight of Starship, outer solar system probes, the Hakuto moon lander and an Indian gravitational wave detector

Starship flies, briefly. Image credit: SpaceX.

As Starship’s engines flickered into life last April 20, it was hard not to feel a surge of excitement. For over two years the world has been waiting for the inaugural launch of Starship and its Super Heavy booster, which together form the most powerful rocket ever built. If all went well the moment could usher in a new era of spaceflight, opening the door to vast new telescopes, space stations and even footsteps on Mars.

Sadly, it did not take long for problems to emerge. The rocket seemed reluctant to leave the ground, lifting so slowly off the pad that for a moment it looked like it would fall back to Earth. Even after, as it cleared the launch tower, it appeared unstable, almost unsure of its path skyward.

Then, fortunately, it found its footing, soaring majestically for almost a minute, climbing on a vast flame of methane. Unfortunately it did not last. Half a minute after lift-off something exploded, emitting a plume of golden sparks. Later other sparks and flames could be seen in the rocket’s flame; signs, perhaps, of failing engines and leaking fuel tanks.

By its third minute aloft, the omens were all too clear. Starship started to spin out of control, cartwheeling over and over in the sky before falling back to Earth. By the time it exploded, some forty seconds after operators had commanded it, the rocket had fallen ten kilometres from its peak altitude.

The first launch of Starship, then, didn’t make it anywhere close to space, let alone orbit. At blame seems to have been a series of engine failures. SpaceX telemetry revealed that three engines, out of a total of thirty-three, had failed in the first few moments of flight. As it ascended several more went out, depriving the rocket of crucial thrust.

That left the rocket far short of the speed and altitude needed to separate Starship and its booster. It may also - though only SpaceX can know for sure - have been the reason why Starship lost control mid-flight.

Many observers were quick to blame the launchpad for the engine problems. Footage of the launch shows vast chunks of debris being hurled into the air. Photographs of the aftermath revealed an enormous crater blasted into the concrete surface. All that debris may have smashed into the rocket’s engines, either knocking them out immediately or leaving them damaged enough to later blow up.

Despite the failed flight, SpaceX are treating the test as a success. They have surely learnt a lot about the rocket and obtained data that simulations cannot provide. That will aid the development of Starship and the Super Heavy, and help to iterate the next version of the rocket.

Another attempt will follow, as Elon Musk immediately declared. Quite when is unclear. The launchpad took a serious beating and will need extensive repair and rework before the next launch. SpaceX say they need at least two months to both complete that and to ready the next Starship for launch. In reality it will almost certainly be longer, but another attempt in 2023 does not look unreasonable.

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Voyager 2 and New Horizons

Forty-six years after departing Earth, Voyager 2 is running low on energy. Its nuclear batteries are fading, slowly depriving the spacecraft of the power needed to run its instruments. In response, operators have been gradually switching off less essential parts of the spacecraft.

As the power output continues to fall, operators had expected to start switching off more critical parts later this year. That would mean disabling some of the scientific instruments onboard, thus cutting the amount of data that the probes collect and send back to Earth

Fortunately, NASA engineers recently found a way to delay that decision for a few years more. Analysis showed that a small amount of power was being reserved for a voltage regulator, a device that stabilises the electrical system in the event of problems. That regulator will now be turned off - slightly raising the risk of electrical damage but freeing up that reserve power for the rest of the craft.

Voyager may have around another decade of useful science in it, but it is not the only probe traversing the outer solar system. Another, New Horizons, has attracted a certain degree of controversy in the past few weeks.

After flying past Pluto in 2015, New Horizons has since been dedicated to examining small worlds in the Kuiper Belt. This region, which extends far beyond the orbit of Neptune, has been little studied in the past. New Horizons is thus still returning valuable and unique data. Yet moves at NASA are afoot to reclassify the mission, changing its focus from planetary science to the heliosphere.

That would likely put an end to efforts to find Kuiper Belt Objects that New Horizons could fly past and reduce the time researchers have to study the dwarf planets in this region. Yet NASA argues that these studies will return little new data. The spacecraft, they say, could be better dedicated to other topics.

A similar move was made for the Voyager missions, once they had flown past the planets. Planetary scientists, however, are aghast. New Horizons will remain in the Kuiper Belt for another few years, they point out, and no other probes are likely to pass through it for several decades. By switching New Horizons’ focus to other areas, we will be missing an opportunity to study worlds we will not visit again for a generation.

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Ispace Crash on the Moon

Japanese company ispace hopes to make a business out of landing rovers on the Moon. To that end they have been working for several years on their Hakuto-R (“White Rabbit”) spacecraft, which functions as a lunar lander.

In autumn last year the first iteration of this spacecraft took flight, heading on a long and slow path towards the Moon. Over several months ispace successfully operated Hakuto, guiding it as far as 1.4 million kilometres from Earth. In March the spacecraft entered lunar orbit, before gradually lowering its altitude over the surface.

As Hakuto made its final descent towards the lunar surface last week, all at first seemed to be going well. Yet thirty seconds before it touched down, controllers abruptly lost communication with the probe. Later statements from the company suggested it had crashed, possibly because it had run short of fuel during the descent.

Hakuto is not the first probe to crash during an attempted landing on the Moon. An earlier mission sent by an Israeli company failed during its descent and smashed into the surface at over three hundred miles an hour. Another, sent by India in 2019, also failed to slow down enough as it descended and likely broke apart on impact.

Still, private interest in the Moon is running high. Two American companies, Astrobotic and Intuitive Machines, have landers scheduled for launch later this year. Ispace, for their part, are already planning to try again. A second version of Hakuto-R is planned for lift-off for 2024.

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India Plans a Gravitational Wave Detector

The Indian government has approved plans to construct a new gravitational wave observatory in the country. The centre, which will be one of only a handful around the world, will be built in partnership with the Advanced LIGO facilities in the United States.

As well as providing a boost to Indian physics, the new facility will also expand a growing global network of such observatories. Three currently operating stations - two in America and one in Europe - allow researchers to track gravitational waves as they wash over the Earth. One extra station, in Japan, will soon join them, expanding the capabilities of this network.

With a fifth observatory, as planned in India, researchers will have a truly global network capable of pinpointing the exact source of incoming waves. It should also improve coverage of the sky, giving researchers an almost constant ability to watch gravitational waves sweeping across the Earth.