Wednesday, September 28, 2022

NASA mission off to poor start after Astra failure

When Astra’s tiny Rocket 3.3 lifted off from its pad at Cape Canaveral Space Force Station on June 12, all was well. In fact, the mission was progressing to plan until the end – the booster’s second stage aether engine was operating normally until it suddenly stopped, about a minute ahead of time. Unfortunately, the orbital mechanics are nothing if not accurate, and an engine burn that ends a minute earlier as well would never have happened.

According to telemetry values ​​shown on-screen during live coverage of the launch, the upper stage of the booster tops out at a velocity of 6.573 kilometers per second, which is significantly less than the 7.8 km/s required to achieve a stable low Earth orbit. While the video feed was cut off as soon as it became clear that something had gone wrong, the harsh physics of spaceflight means there is little question about the sequence of events. Without the energy needed to stay in orbit, the rocket’s upper stage would have been abandoned in a suborbital trajectory, eventually re-entering the atmosphere and burning up a few thousand kilometers below where it started.

An unusual white plume appears from the engine when suddenly stopped.

Of course, it’s no secret that space flight is hard. The startup certainly has only a few successful flights under their belt. There is no doubt that Astra will determine why their engine shut down early and make whatever changes are necessary to ensure it doesn’t happen again, and if their history is any indication, So they are likely to fly again in short order. Designed for Defense Advanced Research Projects Agency (DARPA) competition, which sought to spur the development of cheaper and smaller rockets capable of launching payloads at shorter times, Astra’s family of rockets had already achieved unusually high Has demonstrated operational agility.

Astra, and the Rocket 3.3 design, would survive to fly again. But what was the payload to put the booster into orbit? It’s a bit more complicated. It was the first of three flights that were planned to assemble a group of small CubeSats as part of NASA’s Tropics mission. The space agency has already issued a statement saying that the mission can still achieve its scientific goals with low coverage, assuming the remaining satellites reach orbit safely. But if one of the next launches fails, both of which are currently scheduled to fly on Astra’s rocket, it seems unlikely that the Tropics program will be able to achieve its primary goal.

So what exactly is the tropics, and why has NASA rested its success on the ability of a small and relatively immature launch vehicle to make multiple flights with its hardware onboard? let’s take a look.

getting closer to action

There is no shortage of weather satellites in Earth orbit, but they operate largely in isolation from each other. Partly because they are all of different ages and technical ability, but largely because they were always designed as stand-alone missions. Time-resolved observations of precipitation composition and storm intensity with the Constellation of SmallSats (Tropiques) mission aims to fundamentally change that approach by using a constellation composed of similar CubeSats in low Earth orbit. These craft are outfitted with high-resolution microwave radiometers that can scan satellite tracks on the ground, and with careful alignment of their orbital planes, scans of a given storm on a roughly hourly basis. should be able to provide.

Compared to more traditional satellites, even the relatively modern NOAA-20 that was launched in 2017 is a huge improvement. Working independently, these satellites may be able to image only one storm every four to six hours, which leaves significant gaps in coverage. The rapid scans made possible by the Tropics constellation promise to significantly improve our ability to predict and track deadly tropical cyclones, which have become increasingly more common in the Central and North Atlantic regions. According to NASA, the region saw a record-breaking 30 named storms in 2020, and climate models expect things to only get worse from here.

Tropix was designed to use six 3U CubeSats, each 36 cm (14.2 in) long and weighing just 5.34 kg (11.8 lb). With the loss of the first two satellites on 12 June, the constellation is now reduced to just four. The remaining satellites will still be able to image tropical storms, and will undoubtedly deliver useful data, but less global coverage means the time between flyovers will increase. However it should be noted that even at reduced capacity, Tropics should still be able to provide data much more rapidly than existing platforms.

Starting off disappointingly, it must be remembered that the Tropics is ultimately a low-cost experimental mission. Even as all three launches had been planned, the mission was only supposed to last a year. By the time a single Tropics CubeSat is able to reach orbit and use its instruments to scan for active tropical storms, the mission’s scientific goals will be accomplished – if not aspirational.

special Delivery

Naturally, one may wonder why there is a need to launch just a bunch of six satellites on three separate rockets. After all, SpaceX is launching 60 of its Starlink satellites per launch to build its own constellation. Couldn’t all six Tropics CubeSats have been taken into orbit at the same time if NASA had booked their route on a more powerful rocket?

Technically, yes. But again, they would not have been placed in suitable orbital planes to achieve the mission’s stated goal of hourly overflights. This target is believed to be already unreachable due to the unexpected loss of the first pair of spacecraft, but if they had all converged along the same orbital track their coverage would have been limited to that of conventional weather satellites.

Dozens of new Starlink satellites are set to be deployed in 2019.

Could the satellites, once dropped, not maneuver in their appropriate orbits, like the Starlink satellites do? Maybe if they were bigger, and had a sufficiently powerful propulsion system. But changes in the orbital plane (that is, changing the inclination at which a spacecraft orbits with reference to the equator) take an incredible amount of energy, especially in low Earth orbit, and in small 3U CubeSats Just don’t have the ability to maneuver. of that scale.

Given the specific goals of the mission, and the limitations of flying smaller and cheaper satellites, Astra’s rocket really is the perfect vehicle to take to the tropics. In fact, the requirements for this mission are not so far removed from the original DARPA competition that Astra developed its own booster for it. The military wanted a rocket that could quickly and cheaply put small satellites into very specific orbits on Earth for reconnaissance purposes, just so that these specialized satellites could exceed the strength and speed of tropical storms compared to soldiers and tanks. are worried.

That is why, despite this disappointing setback, the next two batches of Tropic satellites will almost certainly fly on Astra’s rocket, although they will now have to wait until the investigation into the June 12 failure incident is complete. While other smaller boosters like Rocket Lab’s Electron and even Virgin Orbit’s LauncherOne could potentially be necessary, the cost and expense of adapting the mission to a new launch vehicle should not be underestimated. Furthermore, as it is said: Better late than never,

Nation World News Desk
Nation World News Deskhttps://nationworldnews.com
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