Goodbye EO-1

Last week I had to say goodbye to an old friend, a 17 year-old spacecraft called Earth Observing-1 (EO-1).

"EO-1 was a technology validation mission for testing cutting-edge advancements that have been and are being implemented on current and future satellite missions. The satellite launched in 2000 with 13 new technologies, including three new instruments, that had never been flown previously. Among its many accomplishments, the satellite was an innovator for detecting Earth’s biochemical constituents in unprecedented detail, a pathfinder for using artificial intelligence software for streamlined satellite communication and a precursor for extremely close flying between orbiting satellites."


For me, the EO-1 mission was the start of my career. I was fresh out of college with a B.S. in Aerospace Engineering and I had just landed a job with a very small company in Lanham, Maryland that provided engineering services for NASA at Goddard Space Flight Center. Within a few months of starting work I received my first major work assignment...ascent maneuver design work on the EO-1 mission. My main task on EO-1 was to figure out how to get the spacecraft from the orbit that the launch vehicle initially puts it in on launch day to the orbit it wants to be in operationally. EO-1 was a technology demonstrator mission and one of the technologies it was testing out was autonomous formation flying. If you have ever seen the Blue Angles or the Thunderbirds at an air show then you have seen formation flying...except this is with spacecraft. EO-1 was supposed to fly very close (about 1 minute behind) Landsat-7, a spacecraft that in 2000 was already in orbit above the Earth.

This image shows LandSat-7 in the lead with EO-1 imaging the same swath of the Earth 1-minute later

This image shows LandSat-7 in the lead with EO-1 imaging the same swath of the Earth 1-minute later

One minute may not seem all that close, but remember these are very expensive spacecraft and there isn't anyone sitting in the cockpit in orbit with them. Up until this point in time, if you wanted to move one of these spacecraft it would take days if not weeks of planning before the orbit maneuver was executed and the spacecraft was moved. With the technology we were demonstrating on EO-1 we were going to let the computer on-board EO-1 do all the maneuver calculations and execute the maneuver...all without anyone on the ground having to do anything. This was a first for NASA!

So my first task was to work with a very small team to come up with the sequence of maneuvers that would move EO-1 from the orbit it starts in after launch to a very tight formation flying orbit behind Landsat-7. Getting all of the orbit parameters just right to achieve the tight orbit we needed with Landsat-7 was no easy task and we needed to do it quickly and with as little propellant as possible...you know, so the spacecraft could continue to fly for 17 years! This work lead to my first professionally published paper.

The orbit ascent maneuver design wasn't my only task on EO-1. I helped out a bit with the on-orbit software the would perform the autonomous maneuver calculations as well, but my main task was leading the operation team that help operate the spacecraft from the ground (when the spacecraft wasn't testing out its autonomous capabilities). This involved writing a lot of scripts (computer code) that would generate products needed by other systems that supported the EO-1 spacecraft. Things like ground stations that would track EO-1 and help us communicate with the spacecraft. Ground stations needed to know where to point and for that they needed to know where EO-1 was in orbit above the Earth. So we had to generate specifically formatted files to tell the ground stations what they needed to know. I also had to write scripts to tell the spacecraft how to maneuver. It was one thing to figure out how long to turn on the spacecraft thrusters for, but then you had to tell the spacecraft in its own language how to do that. So we needed computer code to take a maneuver design (point the spacecraft here and burn for this long) and turn it into commands the spacecraft would understand.

So for several years leading up to the EO-1 launch in 2000 I worked on all of these things and then we launched. After launch I lead the team that used the maneuver strategy we designed to actually maneuver the spacecraft into its operational orbit. After EO-1 was safely behind Landsat-7 I also helped with the day to day orbit maintenance maneuver design and the efforts for testing out the autonomous algorithms on-board. After the autonomous maneuvers technology was successfully demonstrated I helped to train the operational team that would take over from there, doing the day to day things to support maneuver operations going forward.

EO-1 was an amazing start to my career. If you had told me as a kid that would be maneuvering a several hundred million dollar spacecraft right out of college I would have called you crazy. But I was in the right place at the right time I got to learn under some of most experienced and truly wonderful people I have ever had the privilege of working with. So EO-1 was more than just a spacecraft to me, it was the start of an amazing adventure that I am still on today. In fact, just last year as I was taking one of my last tests to get my Masters degree I had a question about the maneuver design for the EO-1 mission. I never in a million years thought I would be asked a test question about space that was based on my work.

EO-1 was "turned off" on March 30th 2017. This means the spacecraft was taken out of its operational orbit and put into an orbit that atmospheric drag will slowly and naturally cause to become lower and lower until in burns up in the atmosphere around 2056. So EO-1 may no longer be operational, but its kind of nice to think it will still be up there in orbit long after I retire. Thanks EO-1 and Godspeed...

My History with the Delta II Rocket

Tonight in just a few hours I will be on console to launch the NASA mission OCO-2 (Orbiting Carbon Observatory) on a Delta II launch vehicle. If you have noticed I haven't been posting as much content and as frequently as normal and that is because things get a little busy in the weeks and months leading up to a launch. As I am sitting in my hotel room relaxing before having a late dinner and going in for the launch, I am thinking back on my past missions I have worked that have flown on a Delta II launch vehicle:

EO-1 (Earth Observer-1):

EO-1 was my first assignment straight out of college. My role in this mission was the Lead Flight Dynamics Engineer at Goddard Spaceflight Center (GSFC) in the Flight Dynamics Facility (FDF). EO-1 is a technology demonstration mission, among other things. The main technology it was demonstrating was an autonomous maneuvering capability. This was the 1st time a NASA spacecraft had performed a maneuver (engine burn) on orbit without ground command interaction. The science for the mission was the "Observer" part of the name. EO-1 was following very closely behind a satellite called LandSat-7, which is also an Earth imaging spacecraft. My role in the mission was to design and execute the maneuvers on-orbit to fly EO-1 into the correct position behind Landsat-7 so they could take images of the same place on Earth at about the same time (which allows them to compare the data). So my job was all about calculating orbits. I even co-authored a paper about how the analysis we performed for the EO-1 formation flying that was required for the mission (you can read it here).

Mission Details:

Launch Vehicle: Delta II 7320 (the same configuration as for OCO-2)

Launch Date: Nov 21 2000

Launch Site: Vandenberg SLC-2 (same location we are launching from tonight)

Operational Status: Still operating under a mission extension

MAP (now called WMAP)

MAP (or WMAP as it is now called) stands for Wilkinson Microwave Anisotropy Probe. I started working on the mission design for WMAP before EO-1 even launched. My job with WMAP was to help design the maneuvers it had to perform after separating from the launch vehicle. The interesting thing about WMAP for me was that I got to see both sides of the mission. I was interviewing right around the time of the launch with the Launch Services Program. So I was in Florida and got to see the launch...my 1st launch viewing! I then got on a plane back to Maryland so I could get back to GSFC and help maneuver the spacecraft. The science WMAP was going after was to map the cosmic background radiation (low levels of energy left over from the Big Bang). For more information on the science results from WMAP go here.

Mission Details:

Launch Vehicle: Delta II 7425 (one more solid rocket motor than OCO-2 + an upper stage)

Launch Date: June 30 2001

Launch Site: Cape Canaveral Air Force Station (CCAFS)

Operational Status: Retired from service after 9 years, in a disposal orbit around the Sun

Mars Opportunity Rover (MER-B)

The Mars Opportunity-B (MER-B) mission was a launch training mission for me. I was backup on launch console and in training mode behind the primary NASA flight design engineer. This was my first Delta II launch experience since coming to work for the NASA Launch Services Program (LSP).

Mission Details:

Launch Vehicle: Delta II 7925H (6 more solid rocket motosr than OCO-2 + it was a heavy configuration)

Launch Date: July 7 2003

Launch Site: Cape Canaveral Air Force Station (CCAFS) Operational Status: Still operating on the surface of Mars


[SWIFT][sw] was a spacecraft with one main purpose, to quickly (or swiftly) detect, observe and alert Earth and other space based telescopes of the existence and location of a Gamma Ray burst (or GRB). By the time GRB's are detected on Earth we have missed much of the science concerning GRBs because they are very short lived events. SWIFT was my first mission to sit console on a Delta II mission for as the primary NASA engineer (launch vehicle flight design engineer). SWIFT is still detecting GRB's today and producing some really great science. In fact, each time SWIFT detects a new GRB it send a push notification to my phone. You can get the same alerts from SWIFT if you download the [SWIFT Explorer iOS app][app].

Mission Details:

Launch Vehicle: Delta II 7320 (the same configuration as for OCO-2)

Launch Date: Nov 20 2004

Launch Site: Cape Canaveral Air Force Station (CCAFS)

Operational Status: Still sending me push notifications to my iPhone about GRBs

As I look back I realize that even though I have launch missions on other vehicles besides Delta II, I really started my career with Delta II launched missions. OCO-2 is the 1st of the last 4 NASA missions to fly on a Delta II rocket, so I guess it is fitting that I get to be a part of one of the last few NASA launched Delta II missions considering how I started my career. My role in this particular Delta II launch is much different than the role I played in my previous Delta II missions. This is my 1st Delta II launch as an LSP Integration Engineer (or IE). My job tonight on console as a NASA IE is to make sure there are no issues with the spacecraft while it is preparing for launch on the launch pad. If there are issues with either the rocket or the spacecraft and the issue directly affects the spacecraft, I am the main NASA engineer that helps communicate and work those issues between the spacecraft team and the Delta II launch vehicle team. My call sign tonight on console is "NASA IE".

If you are actually awake and want to follow the launch online (launch is at 2:56 am pacific time), you can watch the following:

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