PHONESATS

July 12, 2014


I really don’t know how I missed this one.   This document deals with “phone sats”.  You can get a better feel for the technology by taking a look at NASA press release 13-107.  Let’s do that right now.

RELEASE: 13-107

NASA Successfully Launches Three Smartphone Satellites

WASHINGTON — Three smartphones destined to become low-cost satellites rode to space Sunday aboard the maiden flight of Orbital Science Corp.’s Antares rocket from NASA’s Wallops Island Flight Facility in Virginia.

The trio of “PhoneSats” is operating in orbit, and may prove to be the lowest-cost satellites ever flown in space. The goal of NASA’s PhoneSat mission is to determine whether a consumer-grade smartphone can be used as the main flight avionics of a capable, yet very inexpensive, satellite.

Transmissions from all three PhoneSats have been received at multiple ground stations on Earth, indicating they are operating normally. The PhoneSat team at the Ames Research Center in Moffett Field, Calif., will continue to monitor the satellites in the coming days. The satellites are expected to remain in orbit for as long as two weeks.

“It’s always great to see a space technology mission make it to orbit — the high frontier is the ultimate testing ground for new and innovative space technologies of the future,” said Michael Gazarik, NASA’s associate administrator for space technology in Washington.

“Smartphones offer a wealth of potential capabilities for flying small, low-cost, powerful satellites for atmospheric or Earth science, communications, or other space-born applications. They also may open space to a whole new generation of commercial, academic and citizen-space users.”

Satellites consisting mainly of the smartphones will send information about their health via radio back to Earth in an effort to demonstrate they can work as satellites in space. The spacecraft also will attempt to take pictures of Earth using their cameras. Amateur radio operators around the world can participate in the mission by monitoring transmissions and retrieving image data from the three satellites. Large images will be transmitted in small chunks and will be reconstructed through a distributed ground station network. The JPEGS shown below will give indication as to the orbit.

phone-sats (1)

 

FLIGHT PATH

The systems are now operating properly and orbiting Earth delivering information that will be used in evaluating the program.  I feel NASA has married the private and public sectors to produce workable technology that will represent much lower costs yet, hopefully, the same results. Time will tell. According to Chad Frost, Chief of the Mission Design Division at NASA Ames, “We all carry around smartphones these days, so we’re intimately familiar with what a smartphone is and what it can do.  And a few years ago, we had the intriguing idea that you might actually be able to build a spacecraft around a smartphone. So, we were very intrigued by the notion that you could build a very small spacecraft based entirely on consumer electronics devices and other low-cost systems.”

THE CONFIGURATION:

JPEGs of the configuration may be seen by the following JPEG:

phonesat_2_5--NASA

PhoneSat is a nano-satellite, categorizing the mass as between one and ten kilograms. Additionally, PhoneSat is a 1U CubeSat, having a volume of around one liter. The PhoneSat Project strives to decrease the cost of satellites while not sacrificing performance. In an effort to achieve this goal, the project is based around Commercial Off-The-Shelf (COTS) electronics to provide functionality for as many parts as possible while still creating a reliable satellite. Two copies of PhoneSat 1.0 were launched mid April 2013 along with an early prototype of PhoneSat 2.0 referred to as PhoneSat 2.0.beta.  PhoneSat 2.4 is sitting on the launch pad ready for lift-off.  The PhoneSats use a Google Nexus smartphone running the Android 2.3.3. operating system.  Two of the PhoneSats have standard smartphone cameras that were used to take images of Earth from space.   The first JPEG in this post shows one of those pictures.

Now, here is a fact that blows me away.  NASA engineers kept the total cost of the components for the three prototype satellites in the PhoneSat project between $3,500 and $7,000 by using primarily commercial hardware and keeping the design and mission objectives to a minimum.
NASA added items a satellite needs that the smartphones do not have — a larger, external lithium-ion battery bank and a more powerful radio for messages it sends from space. The smartphone’s ability to send and receive calls and text messages has been disabled.  Each smartphone is housed in a standard cubesat structure, measuring about 4 inches square. The smartphone acts as the satellite’s onboard computer. Its sensors are used for attitude determination and its camera for Earth observation.

TESTING:

There are several phases to “powering-up” the PhoneSat system.  These are as follows:

Phase 1: After the initialization phase, the phone is in phase 1 in which it performs a health check. During this phase, each sensor and subsystem is checked and data is compiled into a standard health packet, stored in the smartphone’s SD card and transmitted over the beacon radio at a regular interval of 30 seconds. The last 10 health packets are stored in the SD card. After every 10 packets sent, the beacon radio is rebooted. This phase happens during the first 24 hours of the mission. The mission time is kept in the phone throughout the mission so that a system reboot during this phase does not reset the 24 hour countdown A health packet consists of: Satellite ID, restart counter, reboot counter, Phase 1 count, Phase 2 count, time, battery voltage, temp 1, temp 2, accel X, accel Y, accel Z, Mag X, Mag Y, Mag Z, text “hello from the avcs”.

Phase 2: This phase starts once a full system health check has been performed. During this phase, image packets and health packets are sent to Earth through the beacon radio. A health packet is sent once for every 9 image packets downlinked.

This phase can be divided in 3 sub-phases:

• Health Data Measurements: Health data is measured and the 10 most recent samples are stored in the SD card.

• Health Data Downlink: Once 9 packets have been sent through the beacon containing image information, the 10th one is reserved for a health packet.

• Image Sequence: One picture is taken every minute until 100 pictures are taken and stored to the SD card. Pictures are then analyzed and the top image is selected. This image is packetized and compiled into standard image packets. These image packets are transmitted over the beacon radio coupled with health packets in the ratio explained above.

Safe Mode: If the watchdog detects that the phone is not sending any data to the radio for a certain period of time, the spacecraft functionality is reduced to the bare minimum. In this condition, the spacecraft only transmits health data containing the last 10 sensor data values stored in the SD card prior to failure. This mode lasts for 90 minutes. After this period, the spacecraft resumes its normal operations. A safe mode packet consists of: Satellite_ID, last 10 voltage values, last 10 temperature sensor 1 values, last 10 temperature sensor 2 values, text “SAFEMODE”.

TIMELINE:

The timeline for research and development started in 2009. Definite planning has gone into the program.  You may see that timeline below.

TIME LINE

As mentioned above, PhoneSat 2.0 has already been scheduled for launch later on this year, 2014.  The technology is definitely evolving. NASA is working towards extremely low-cost deployments that provide workable communications to government agencies and private concerns.

I welcome your comments.

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