endurance
NASA’s persistence was on its way to Mars on July 30 with a United Launch Alliance Atlas V. It was the last of the three Mars probes for 2020 to depart, and it will be the last to arrive. But it does land, and the sheer amount of video and other data it should send back will definitely make its arrival the most exciting.
When it comes to perseverance, the details of this mission are difficult to explain better than the “everyday astronaut” Tim Dodd in this video. Tim is excellent at explaining what NASA is trying to achieve with this mission, how it differs from the Curiosity rover that landed in 2012, and whether you’ve forgotten how terrifying NASA’s current landing system is for those large probes one look. The Sky Crane system seems absolutely incredible, but it has worked before. Cross your fingers in just a few days, it will work again. Oh, and Perseverance is bringing the Mars helicopter – a small drone that can hopefully fly around in the world’s thin atmosphere and provide new angles in the landing zone.
As a bonus this time around, Perseverance has new cameras with which to record most of what happens during the “seven minutes of terror” associated with the complex landing. But getting those images back will only happen if the terror ends happily.
If you don’t see anything else, check out this landing system. Terror is terrifying for every engineer. If you’re wondering why they do this, here’s a quick rundown. First, the Martian atmosphere is too thin for a parachute of any practical size to slow such a heavy lander to a reasonable speed. So it takes missiles to really brake. However, the surface of Mars is littered with stones and sand that could be hit by missiles to damage the lander. Solution – keep the missiles in the air and hang the lander on ropes. Seriously.
hope
The UAE’s Mars mission is a truly international affair. The Hope probe itself was built on Atmospheric and Space Physics Laboratory at the University of Colorado, in collaboration between American and Emirati engineers. In addition to research centers in the UAE, both the University of Arizona and UC Berkley were involved in the design and construction of the probes. After its completion at LASP, Hope flew to Japan on a Ukrainian Antonov An-124 cargo jet. Eventually it was mounted on a Mitsubishi H-IIA rocket and launched from JAXA on July 19 from Tanegashima Space Center. All of this happened in the middle of the pandemic, with scientists and engineers quarantined at each new location, and they made it to the launch window in time. It is amazing. When it arrives, Hope will devote most of his resources to studying Martian weather, including monitoring dust storms and looking at the changes caused by the seasons on Mars.
Like Perseverance, Hope has a white knuckle finale for its arrival on Mars – in this case, a 27-minute burn that is supposed to put the probe into orbit. This is a big deal not just for the UAE but for the entire Arab world, who see this as yet another sign of the regions coming onto the world stage.
heavenly questions
The name of China Tianwen-1 roughly means “heavenly questions”. Hopefully the orbiter and lander will actually provide some solid answers from this multi-year mission to Mars. The probe launched on July 23, 2020 – in the middle of this optimal window for a quick journey to Mars – a long-throw rocket on March 5.
Unlike Perseverance, which will scream into Martian atmosphere at high speed, like Hope, Tianwen-1 will do a long orbital engine fire that will put the entire hardware collection into Mars orbit. The orbiter hardware is already collecting information, including not only images, but also analyzes of cosmic rays and other high-energy particles in space around Mars.
If everything goes as planned, the lander will fall off orbiter in May and make its way to a location in the southern part of Mars’ Utopia Planitia – a large, flat plain that may not be the most interesting landscape on the planet, but it does should provide good terrain for a safe landing. Like Perseverance, Tianwen-1 will use both a parachute and missiles as it descends. As a much lighter vehicle, however, it won’t use anything like the sky crane system. Instead, the Chinese hardware is designed more like previous American systems like Pathfinder, with a larger lander weighing a small rover.
If China successfully lands on Mars, it will probably only be the second nation to do so. The Soviet Union’s Mars 3 lander landed seemingly gently in 1971, but failed less than fifteen seconds later after returning only part of an image. Since then, the British Beagle 2 appeared to be making a safe touchdown but was never communicated, and the European Space Agency’s Schiaparelli lander made a very non-soft touchdown (i.e., it crashed).
Mars is difficult.
SLS fires again
The Space Launch System is the seemingly unfortunate result of a long, long program to replace the space shuttle with a flexible system that can get astronauts into orbit, back to the moon, and possibly beyond. The challenge involved scrapping an entire program and building the current system from parts of parts from previous programs. That should make it both cheaper and easier. It didn’t work out that way.
After an edition that can keep up with the development of the shuttle, NASA now only has one SLS core on a test bench at NASA’s Stennis Space Center in Mississippi. This core includes four RS-25 Engines that have previously flown as main engines on space shuttles. All four have now been upgraded to be even more powerful. When the SLS actually starts, these engines are accompanied by two solid fuel rocket boosters, similar to those on the shuttle, but longer. All in all, SLS achieves a maximum thrust of 8.8 million pounds – making it about 15% more powerful than a Saturn V. (Although for complex reasons SLS can deliver less payload to the moon than its famous predecessor.)
On January 16, NASA invited journalists and the public to view a test fire from SLS. It should take eight minutes, the time it would take for the engines to get the rocket into orbit. However, that test was abandoned after just over a minute, re-casting doubts about a program plagued by setbacks, delays and cost overruns. With a new government moving in just days later and future priorities for NASA unclear, there was a fair chance the failed test would be the last breath for SLS.
However, President Biden has expressed his support for both SLS and the Artemis program that aims to bring astronauts back to the moon in the next few years (the target is actually 2024, although no one is actually buying that target). With this support, NASA decided to conduct a second test fire of the SLS, which will last at least four minutes. The test fire is now scheduled for February 8th.
Upon successful completion, the SLS core will be loaded onto a barge and taken to the Kennedy Space Center, where the Artemis-1 mission is to be launched. This mission is expected to send an unmanned Orion crew capsule around the moon, approaching Apollo 8 (excluding the astronauts) and representing the first “full-stack” test of all SLS / Artemis hardware. In theory, that mission could still fly in 2021, but the decision to keep SLS for a second hot fire in Stennis likely means Artemis-1 is now slipping to 2022.
Spaceship tries again. And again.
On February 2, SpaceX carried out a second high-altitude flight of its large spacecraft rocket. And as befitting Groundhog Day, Starship SN9 repeated the flight of Starship SN8 with a successful flight and a highly unsuccessful landing.
Starship is part of an offer from SpaceX to produce a system (Superheavy Booster plus Starship Upper Stage) that together can launch massive payloads while being fully reusable. If successful, they could reduce the cost of orbit material by a factor of 100. This is a necessary step if SpaceX founder Elon Musk really wants to build these cities on Mars, but it could also be a big step forward in almost any other thing that could happen in space.
To make it work, Starship has a unique country style. The stainless steel ship “flops” into the atmosphere and then comes down sideways with canards at the front and fins at the back to adjust its attitude and steer towards the landing site. Then, literally in almost the last second, the rocket fires its engines, spins upright, and lands gently. Theoretically.
On SN8, the flight was great until the last few seconds when one of the two engines ran out of fuel and started burning its own hardware, resulting in a failure and crash. On SN9, the flight seemed to go wonderfully right up until the last moments when one of the landing engines failed to restart. The result was an even harder impact from a momentary mushroom cloud of fire. SpaceX has run a “hardware rich” program in which they are willing to make mistakes in order to move forward. It is not clear, however, that anything other than “What we do doesn’t work” was learned from SN9.
Starship SN10 was already sitting on a pad when SN9 took off and is expected to get a chance to fly in the next few weeks. If so, SpaceX will likely make some adjustments – like trying to light all three engines on landing and then turning off any problems instead of trying to light the bare minimum. If SpaceX can do this job, Starship could not only pitch over 100 tons of payload, but potentially carry 100 people as well. Really. It’s so big
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