IV&V’s Contribution to JPSS-1

Update: (Vandenberg Air Force Base, Calif., Nov. 6, 2017) – The ULA Delta II rocket carrying the JPSS-1 mission for NASA and NOAA is delayed due to a faulty battery. The delay allows the team time to replace the battery on the Delta II booster. The vehicle and spacecraft remain stable. Launch of the JPSS-1 mission is scheduled for no earlier than Tuesday, Nov. 14, 2017.

There isn’t just one satellite hovering above Earth that provides humans the ability to constantly monitor the potentially dangerous weather, but rather there are actually several of them. Soon, there will be one more hovering up there when the Joint Polar Satellite System (JPSS) adds JPSS-1, the second of what will be a five-satellite JPSS constellation, when JPSS-1 launches on November 10, 2017. While the construction of the satellite itself was managed by NASA, once it is launched, it will belong to the National Oceanic and Atmospheric Administration (NOAA). NOAA operates 16, soon to be 17, satellites in various orbits, ranging from low Earth orbits (LEO), starting at around 200 miles above the Earth, all the way out to geostationary orbits (GEO), which is around 22,000 miles above the Earth. The newest of NOAA’s fleet, JPSS-1, will be launched from Vandenberg Air Force Base in California, as Vandenberg provides the best US-based launch location to place JPSS-1 in its own unique LEO orbit, called a “polar sun-synchronous” orbit. This particular type of orbit will allow JPSS-1 to circle the Earth from pole-to-pole at an altitude of about 512 miles above the Earth’s surface, crossing the equator 14 times daily, and allowing for full global coverage with its five onboard weather-hunting instruments twice a day!

What do these instruments do and how do they help me?

The instruments on board JPSS-1 provide real-time environmental data that allow people around the world to make important decisions about protection of life and property, national security, economic interests and vital environmental resources like coasts, oceans and ecological habitats. Of course let’s not forget they also provide some of the essential data for those weather maps your local meteorologist uses on the nightly news. The Advanced Technology Microwave Sounder (ATMS) and Cross-track Infrared Sounder (CrIS) are two instruments that work together to provide profiles of atmospheric temperature, moisture and pressure. The Visible Infrared Imaging Radiometer Suite (VIIRS) provides daily high-resolution imagery and radiometry across the visible to long wave infrared spectrum (those weather maps that were just mentioned). The Ozone Mapping and Profiler Suite (OMPS) uses a spectrometer with UV bands for ozone measurements. Finally, the Clouds and the Earth’s Radiant Energy System (CERES) works as a scanning radiometer, which measures reflected sunlight and thermal radiation emitted by the Earth. Versions of all five of these instruments have flown on previous satellites, but all the instruments that are going up on JPSS-1 have been improved since they were last flown. That means that with these upgraded instruments, JPSS-1 will be more effective in forecasting flooding, tropical cyclones, hurricanes, tornadoes, blizzards and other high-impact weather events, providing more lead time to for Earth’s inhabitants to make important life and property decisions. JPSS-1 will also help in assessment of environmental hazards such as droughts, forest fires, poor air quality, and harmful coastal waters.

How did NASA Independent Verification and Validation (IV&V) Program play a part in the development of the JPSS-1 satellite?

In short, our team worked on the “brains” of the satellite, the flight software (FSW). The primary activities in controlling the satellite were split into two different bins, each being handled by its own processor or computer. The computer that handles the control of the spacecraft, such as extending the solar panel, changing spacecraft attitude, or igniting the thrusters to change orbit, is called the Spacecraft Control Processor (SCP). The Command Data Processor (CDP) is the computer that handles the communications of the spacecraft, both externally to the ground network on Earth and internally to all of the spacecraft subsystems, like the instruments. The CDP is additionally responsible for collecting, storing and downloading to Earth the science data that was captured by the five onboard instruments.

IV&V also assessed the CDP interfacing to two of the instruments, VIIRS and CrIS, as those instruments were using a new-to-JPSS data interface, called SpaceWire, to create a connection from the CDP to those instruments. IV&V followed along with and assessed the development of the FSW from the point when requirements were being determined for what the computers needed to do to satisfy the mission objectives, all the way to the point where the completed FSW was loaded onto the computers, connected to other flight hardware, and was tested to see if it worked the way it was supposed to. IV&V made sure the JPSS-1 FSW works as it is supposed to, does not do what it is not supposed to do, and responds as expected when the spacecraft encounters adverse conditions.

Now with JPSS-1 soon to be watching over us all, we will all be able to watch our nightly weather forecast with much more confidence in determining if we will need our umbrella for the following workday.

Jeremy Fienhold
Systems Engineer

STF-1 Update 2

The Simulation-to-Flight 1 (STF-1) team has been making significant progress since the last blog post. As per the primary mission objective, some software-only simulators have been developed and are currently released as version 1 NOS3 or the NASA Operational Simulator for Small Satellites. These simulators will aid in flight software development that is currently underway.  The current focus is on developing the core applications that will drive the mission. This development phase will last for approximately three months before integration and testing begins. The clean room that will be used by STF-1 has been completed and is ready to accept components that have already started arriving. Below is a picture of the cleanroom ready for the ribbon cutting ceremony here in the coming weeks.

Clean Room

The components have already been arriving and are nearly ready to begin testing. The science teams have already begun designing systems and PCBs that will perform the experiments. The current component status can be seen in the table below. Each science team at West Virginia University (WVU) has been working diligently to meet the delivery date at the end of this year so that testing can begin.

Hardware Status
Onboard Computer Received
Solar Cells Received
Power System Ordered
Chassis Ordered
ITC Designed Solar Panel PCBs Designed – Out for Quote
Radio Ordered
Clean Room Assembled and Setup for Ribbon Cutting
Deployable Antenna Ordered
Camera Received

The anatomy of the spacecraft is depicted below. The chassis selected is the Innovative Solutions In Space three unit design.  This allows for each unit, or cube, to be assembled independently before full spacecraft integration.  The antenna is also specially designed to fit the chassis, depicted on what is actually the bottom of the spacecraft that is upside down in the picture.  Having the antennas on the underside of the spacecraft allows for use of the extra space, nicknamed the tuna can due to its size, in the launcher to house the GPS antenna.

Anatomy of STF-1

OC-Flight-1’s First Flight

Just after 6 a.m. on Aug 13, 2013, the OC-Flight-1 picosatellite payload was flown on a sub-orbital testing experiment as part of the “RockSat-X 2013” competition at NASA’s Wallops Flight Facility. The payload was launched from a Terrier-Malemute sounding rocket to an altitude of ~170km, roughly half the altitude at which the picosatellite will orbit the earth and 70km above the Karman line (conventionally used as the start of outer space).  At this altitude, the shell of the RockSat-X payload canister was ejected and the experiments were exposed to elements of the ionosphere.

The intent of testing this science payload in the upper atmosphere was to increase the level of confidence that each subsystem component will behave as intended during on-orbit operation. Since the team is planning on using low cost components-off-the-shelf (which haven’t been manufactured specifically for space applications), there will be a slight risk of adverse performance. By testing normal operation in space conditions, weak points in the design can be identified and adjustments can be made before a large amount of money is spent launching the satellite into low-Earth orbit.

OC-Flight-1 Picosat
OC-Flight-1’s picosat after suborbital flight.

Although the communication systems test was unsuccessful due to a failure in antenna deployment, the payload data was stored on-board and recovered after the RockSat-X payload canister re-entered Earth’s atmosphere and was retrieved from the Atlantic Ocean 90 miles off shore. Using this data, it was determined that the payload subsystems were functioning properly during upper atmosphere operation and the main testing objective was achieved. Additional testing is in the works to prove the long range capability and reliability of the communications system.

NASA’s IV&V Program partnered with students from West Virginia University to integrate the OC-Flight-1 subsystems with other scientific experiments intended to be performed in the upper atmosphere as part of the overall competition. Other participating universities included University of Colorado at Boulder, University of Puerto Rico at San Juan, University of Maryland, Johns Hopkins University, West Virginia University, University of Minnesota, and Northwest Nazarene University. Even though the team was not alone in encountering mishaps during the integration and operations phase, every team involved with the competition came out a winner. The hand-on practical knowledge gained from participating in RockSat is highly valuable and will be an experience that’s never forgotten.

To see the re-entry of OC-Flight-1’s picosat, watch the video below.

Steven Hard
Project Manager
NASA’s Independent Verification & Validation Program