Saturday, February 25, 2017

ISS: Busy Traffic Week

 Current Spacecraft positions on the ISS. Credit: NASA.

It was a very busy week for the crew of Expedition 50 on the International Space Station. In between station maintenance, science experiments, and preparations for future work, the crew needed to be on their toes dealing with all the intracacies of arriving robotic spacecraft.

Launch Pad 39B with the SpaceX Falcon rocket. Launch Control and the Vehicle Assembly Building seen in the background. SpaceX.

Events started with a roar on Sunday. From the historic LC-39B pad, SpaceX launched Dragon 10, their unmanned cargo spacecraft, on a mission to take supplies to the ISS. The launch went very well, and Dragon began its 2 day voyage to rendezvous with the station. 

First launch from Pad 39B since the retirement of the shuttle in 2011.

In a historic first, the Dragon 10 lifted off from its pad on the Falcon rocket as the first commercial rocket to launch from the famous pad 39, where decades earlier the astronauts flew the mighty Saturn Vs to the Moon in project Apollo, and then later when the space shuttles began their routine missions into low Earth orbit. This pad site has been modified from the shuttle operations to accept more commercially-operated designs. It is currently leased to SpaceX, which previously had been using the Pad 40 on the Cape Canaveral Air Force station. That pad was damaged in a Falcon Explosion in September of 2016. It is expected that future manned SpaceX flights will also take place from 39B.
Separation of Dragon-10 from the second stage. SpaceX.
In a further demonstration of their rocket prowess, the controllers of SpaceX carefully guided the first stage of the Falcon back through the atmosphere to a safe, upright landing at the landing pad on Cape Canaveral. The first stage will be examined, refurbished, and re-used on a future flight to help save funding. 
Dragon-10 approaches the pickup point.
Docking with the ISS proved to have some difficulties. As the spacecraft made its first approach to the ISS, a fault in the GPS tracking triggered an orbit of docking approach and the spacecraft was backed away from the station while engineers investigated the problem. A work-around was configured, and a second attempt the next day was successful. Astronauts Shane Kimbrough and Thomas Pesquet used the robotic arm to grapple and then dock the Dragon temporarily at the Node-2 docking port. They used cameras to record the outer condition of the Dragon for engineers to study later. Then the craft was moved to the Common Berthing Module.
Meanwhile, back in Russia...
In a nice daytime blastoff, the Russian space agency launched a Progress resupply spacecraft into orbit from the Baikonur facility. Known both as MS-05 and as Progress 66, the Soyuz-U rocket used a different third stage motor design than was used on the previous Progress MS-04 mission. That motor suffered a catastrophic failure in the oxidizer turbopump, which shredded the engine and lost the spacecraft in flight.
 Picture-perfect liftoff of the Soyuz-U rocket with Progress 66 aboard. Spaceflight Now.
After an 8-minute flight and stage separations, the Progress 66 ship was on its way to the station. The flight plan for this mission again called for a 2-day orbit path, giving engineers plenty of time to test and verify all functions carefully. The S-band uplink navigation system was able to complete its flight-certification, the last step in preparations to begin using the latest Progress design in the preferred single day orbital approach flight plan.
Progress 66 approaching the ISS, with its solar panels making a symmetrical wing-like appearance.
On Friday, the Progress 66 spacecraft reached its rendezvous point with the station and engineers carefully guided the vehicle into its docking position. The spacecraft completed its flight at the Pirs module docking port. This makes the 68th successful Progress mission to the ISS, delivering supplies and experiments to the station.
The next supply mission expected is the Cygnus mission on March 19.

Saturday, February 18, 2017

50 Years ago: Lunar Orbiters Scout for Landing Sites

Lunar Orbiter Engineering Mockup.
Fifty years ago, in February 1967, NASA pressed on with the preparations for the Apollo missions despite the recent deaths of the Apollo 1 astronauts. The purpose of the Lunar Orbiter spacecraft was to photograph potential landing sites for the Apollo missions expected to occur within the next few years. This particular spacecraft, Lunar Orbiter 3, blasted off from pad LC-19 at Cape Kennedy (Canaveral) on February 5, 1967. 
Lunar Orbiter 3's ride: Atlas-Agena D.
The Atlas rocket was basically the same as those which powered America's first orbital manned missions. The Agena second stage was a fueled and powered-up version of the Agena target vehicles used during the Gemini program. The orbiter itself was built at the Langley facility in Virginia, recently featured in the movie, "Hidden Figures."
Liftoff from Pad LC-19.
Blast off took place before dawn and the rocket lifted the Agena into position where its motors pushed the spacecraft fast enough to defeat Earth's gravity. The Orbiter reached the Moon on February 8. The camera recorded lunar images from February 15 to 23. Over 500 images were taken.
Image from Lunar Orbiter 3.
Image quality was very good, so much so that one image managed to pinpoint the landing spot for Surveyor 1. The spacecraft stayed in orbit in a gradually decaying orbit when it struck the lunar surface in October 1967.