Saft batteries were used in satellites made by Sierra Nevada Corporation (SNC) that were launched into space recently by a Space X Falcon 9 rocket, which lifted off from Florida. 11 new-generation satellites were added to the ORBCOMM telecommunication network during the mission. (It was also the flight that featured a successful landing of the same rocket at Cape Canaveral.)
Yannick Borthomieu, Saft SBG Space Product Manager from France, answered some questions about the batteries used in the satellites.
1. The Saft batteries provide electricity for a satellite when it is blocked from sunlight for up to 35 minutes per orbit during the whole mission. Does each satellite have its own solar power system which provides most of its electricity?
Yes, each satellite has its own power system including solar panels and batteries. When the satellite is in the sunlight, the solar panels provide the power to the satellite for the pay load (communication system) and is the platform for all equipment.
2. What is the mission duration for each satellite?
The OG2 program asked for five years mission time.
3. What is the capacity of each Saft satellite battery system?
Each satellite embarks one 8S6P MPS176065 battery with a capacity rated exactly 33.6 Ah and 29.2 V average voltage.
4. Why did you use lithium-ion batteries for this application?
The lithium-ion (Li-ion) technology offers the lightest battery for satellite applications. The weight saving is the main advantage of the Li-ion system in space applications. Other advantages include self-discharge ratio, heat dissipation and energy efficiency.
5. What are the dimensions of each battery used: weight, height, width.
While specific dimensions are proprietary customer information, we can confirm the battery weight is 12.5 kg.
6. How long does it take the satellite’s solar power system to charge the Saft batteries?
Low Earth orbit satellites have an approximate 95 minute orbit time, with 35 minutes of eclipse and 60 minutes of sunlight. The battery is discharged for 35 minutes when the solar panels are not working due to the lack of sun. It is recharged by the solar panels for 60 minutes.
7. What is the overall operating life of each satellite battery system?
The operational life time is five years, however the overall operating life includes the ground storage time which is five years.
8. What are the 11 new-generation satellites going to be used for?
The total constellation with 17 satellites (with six first launched in July 2014) is used to provide a telecom network for Orbcomm.
9. How was it arranged they would catch a ride into space on the Space X Falcon 9?
The ride on Space X Falcon 9 was arranged by Orbcomm.
10. How do you monitor battery function while a battery system is on board a satellite in space?
The satellite operation can provide telemetries to manage some battery parameters on board such as current, voltage and temperature.
11. What kind of temperatures are your batteries operating in while in space?
The battery temperature range is 10 to 30°C. The battery is placed in a dedicated compartment that ensures a range from 15 to 25°C thanks to heaters which can be connected by the system.
Image Credit: istockphoto.com
Have a tip for CleanTechnica, want to advertise, or want to suggest a guest for our CleanTech Talk podcast? Contact us here.