OSIRIS-Rex: Dinosaur or science mission?

On September 8th, 2016, NASA used an Atlas V (411) ¹ to launch the OSIRIS-REx ² asteroid sample return mission ³ to asteroid Bennu⁴.

So let's review what that means:

1) The Atlas V (411) is a two-staged rocket built and operated by United Launch Alliance that has been in service since 2002, primarily used for launching military satellites and often sending robotic probes to far-off solar system destinations. As launchers go the Atlas V has an incredible reliability record with 65 straight successful launches. There have been a few minor in-flight issues here and there but the "Mighty Atlas" (as ULA's CEO is fond of calling it) always gets the job done. As successful a rocket as it may be, it's not been without controversy. In fact, in the wake of Russia's incursion into Crimea the US government temporarily banned the import of Atlas V's first stage engine because it is built in Russia.

     Atlas V comes in several variants, which is the reason for the "411" code in this instance. That means that it has:

• A 4-meter diameter (13.1 ft) payload fairing that protects the payload during flight through the atmosphere. A 5-meter (16.4 ft) fairing is also available for larger satellites.
• 1 side-mounted Solid Rocket Booster, built by Aerojet Rocketdyne, to provide additional thrust early in the flight. Atlas V can use up to five SRBs.
• 1 Centaur upper-stage engine to take the payload from the upper atmosphere to its final orbit. This upper-stage can have one or two engines.

 Below you can watch the launch of an Atlas V 551, one of the most powerful variants.

For more information, check out ULA's website.

2) OSIRIS-REx is unfortunately NOT a dinosaur but a NASA mission with perhaps the most cumbersome acronym of all time. Its full name is the Origins Spectral Interpretation Resource Identification Security - Regolith Explorer. The mission is designed to visit an asteroid (Bennu) that occasionally passes close to the Earth, to study and characterize it. OSIRIS-REx will

• Measure how sunlight absorbed then re-radiated by the asteroid's surface causes it to rotate and change its orbit around the sun over time--called the Yarkovsky Effect. This could affect how close Bennu comes to Earth--possibly close enough to impact our planet in the future.
• Map the distribution and chemistry of Bennu's surface.
• Return a sample of the asteroids loose rocky, dusty surface material called "regolith." More about this in the section below.

 

3) Asteroid sample return is OSIRIS-REx's primary mission. After orbiting Bennu for an extended time to understand its gravity and rotation, an arm will extend to the surface and release a burst of gas to push surface material into a surrounding screen where 2 to 70 ounces (60 to 2000g) of the material will be captured. That capture device (called TAGSAM) will then be encased in a heat shield and make a fiery return to Earth's surface. This will allow the samples to be handled and analyzed by scientists with a wider range of observational and testing equipment than if mission planners sent a select few instruments into space. It will also allow scientists to save samples for future generations to study with currently-unknown testing processes that may be developed in the decades to come.

4) Asteroid Bennu is a 1,600 ft (500m) wide asteroid and, like all asteroids, is a remnant of the formation of our early solar system. After gravity had gathered most of the material into planets and moons what was left over became the asteroid belt. Radar and visual observations lead scientists to believe that Bennu is extremely high in carbon which also gives it a remarkably low level of reflectivity. This has made observations difficult but OSIRIS-REx's visit will provide first-ever close up imagery and radar data on this asteroid. That data will be compared with Earth-based observation that may reveal better observation methods for the future that could come in handy nearing the years 2175 to 2196 when Bennu stands a 1-in-2700 chance of impacting the Earth. Looks like humans of the future could either use good luck OR good science.


Have you somehow reached the end of this and have a desire to read MORE detailed information about the OSIRIS-REx mission? Well you can click this link for the official mission factsheet.

 

Sounding Rockets

On August 17th, 2016, NASA's Wallops Flight Facility launched a suborbital sounding rocket for the RockSat-X mission. Now...what the heck did all of that mean?

Let's break it down.

NASA's Wallops Flight Facility is an airfield and launch complex at Wallops Island, on the eastern shore of Virginia. For over 70 years this facility has conducted orbital and suborbital (see next paragraph) rocket launches for research purposes, has managed scientific balloon projects, conducted flights to the arctic to measure sea ice change, and launched drones to fly through and measure hurricanes. Most recently this facility has gained attention for being the launch site of Orbital ATK's Antares rocket which resupplies the International Space Station.


A suborbital rocket is one that launches into space but no part of that rocket stays there. Everything that goes up comes back down. Orbital rockets fly a path mostly parallel to the Earth's surface, which is how they end up in a circular orbit around the planet but suborbital rockets often fly very steep vertical trajectories. They fly as low as about 30 miles and as high as 900 miles above the Earth's surface then descend back to the surface. The upper sections of the rocket that carry the science payloads are returned to Earth under parachutes where they splash down in the ocean and are recovered by boat crews. Flights often last as little as 15 minutes.

Sounding rockets get their title from maritime tradition. In the old world of sailing ships, to "take a sounding," meant to drop a weight and length of rope into the water to measure the depth beneath your ship. So "sounding" became a synonym for "measurement." Thus, sounding rockets are simply measurement rockets. They carry a wide variety of science experiments into the upper atmosphere and the reaches of space several hundred miles above our heads for the purpose of measuring natural phenomena that only take place there, to make brief observations of astronomical targets, or sometimes to run brief experiments in microgravity while the rocket is in free-fall back to Earth. The variety of subjects to measure and ideas to test is so extensive that NASA's Wallops Flight Facility has conducted over 16,000 sounding rocket flights.

RockSat-X is a cooperative program where several universities conduct their experiments on the same rocket flight--in this case it was a rocket called a Terrier-Improved Malemute. No, this is not a new dog breed mix, it's a combination of a Terrier booster rocket and a Malemute upper stage. (No, I don't know how they got those names) This particular flight included experiments that observed crystal growth in microgravity, observed how a molten blob of metal cools and reshapes in microgravity, tested the strength and effectiveness of 3D printed airfoil shapes, detected and collected micrometeroids, and a set of HD cameras to watch the deployment of all of these experiments and more. RockSat-X reached 95 miles in altitude and many of the experiments returned their data via radio but unfortunately the upper stage with the experiment hardware was not able to be recovered which means that some of the physical experiments could not be examined in person. For more detailed info on this mission just click here.


If you have any questions about what you just read or would like to read more info on anything mentioned here, please leave a comment or contact me!

Progress - The Swiss Army Knife of Spacecraft

Shortly after noon today, a Soyuz rocket blasted away from the Baikonur Cosmodrome in Kazakhstan, carrying a cargo vehicle known as "Progress" to the International Space Station. There are a number of spacecraft resupplying the ISS these days* but Progress is (arguably) the most versatile.

In order to operate a space station you need a number of recurring services:

• Delivery and return of crew members
• Delivery of consumables (food, water, oxygen, fuel)
• Delivery of hardware (station parts, spacesuit parts, science experiments)
• Removal of waste (food packaging, broken hardware, completed experiment hardware)
• Orbit and/or attitude adjustments (rotate orientation, increase or decrease altitude to avoid orbital debris or to compensate for atmospheric drag--yep, at 250 miles there's still enough air to slow it down!)

Progress can handle all of those tasks but one; carrying crew to and from orbit. The reason for this lack of capability is that Progress is a direct descendant of the crewed Soyuz spacecraft, which has been the workhorse of Russian spaceflight in constant operation (and upgrade) since 1967, with great successes**. Rather than develop a completely new vehicle, the Russian space program chose to adapt their proven design into a cargo-only vehicle.

The Progress is composed of three segments: a pressurized cargo module, a refueling module, and an instrumentation/propulsion module.

The forward, somewhat spherical segment is the pressurized cargo area that will contain nearly 4,000 lb. of hardware, food, and some water that the cosmonauts and astronauts will manually remove once this portion of the vehicle docks with the ISS. In the months after this cargo is unloaded, that same area will be filled with the multiple forms of waste that life inevitably generates.

At the center of the spacecraft is the refueling module. As you can see in the diagram, this segment is filled with a number of tanks that contain fuel, oxidizer, and sometimes water. Not all missions require more water to be transported so there is some variation in this segment. Again, this segment could hold nearly 4,000 lb. The fuel can be transferred from Progress to ISS by connections in the docking ring, where the two spacecraft meet, eliminating the need for crew to be exposed to hazardous materials. As far as I know, Progress is currently the only spacecraft capable of this function, making it that much more important to station operations.

In the crewed Soyuz this space is the descent module where the crew's seats and instruments are located. To return to Earth, the forward segment and propulsion segment behind it would detach and a heat shield between descent and propulsion modules would protect the crew during atmospheric reentry. No such shielding is needed for Progress. Remember all that trash to be loaded in the cargo area? It's meant to be burned during atmospheric reentry.

The final segment at the rear of the vehicle not only does the work of navigating Progress to the ISS, it also serves as an instrument of orbital adjustment. While the ISS has it's own on-board engines for attitude and orbit adjustment, it is wiser to use those of the visiting spacecraft because the hardware on the ISS must remain on orbit for years (in the end it will be multiple decades) while the visiting spacecraft is newer and more recently inspected to assure safe and effective operations. This also reduces the need to transfer fuel between vehicles. The Space Shuttle was able to facilitate these orbital adjustments but that system was retired in 2011. The Japanese HTV can also provide reboosts but is an infrequent visitor to ISS, leaving the Russian Soyuz and Progress to do much of the work.

So as you can see, Progress really serves as many vehicles. It is the delivery truck, it is the fuel tanker, it is the tow truck, and it is the garbage truck for the International Space Station. It's not glamorous work but it all has to be handled. With all of these support tasks taken care of, the crew can get down to their true purpose on orbit: scientific experiments that, in one way or another, will advance the knowledge and abilities of humanity as a whole. So I suppose you could say that ISS needs Progress to enable progress.

Has there ever been a more appropriately named vehicle?

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*Current: Progress (Russia), Dragon (USA), Cygnus (USA), H-II Transfer Vehicle (Japan)
  Retired: Space Shuttle (USA), Automated Transfer Vehicle (Europe)
  Future:  Dream Chaser (USA)

**Of course, Soyuz has also had its set of failures. But that's a matter for another time.