MOST space telescope turns 15, and a secret is told

posted Jun 30, 2018, 6:18 PM by Doug Sinclair

Today is the 15th anniversary of the launch of the MOST space telescope.  This little mission was ground breaking for both its science and its technology.  Scientifically, it has observed oscillations in stars in a way that no other instrument could.  Technically, it demonstrated sub-arcsecond pointing stability in a microsatellite platform for the first time.  And after all this time it is still working and producing useful science.

I built a rather unusual power system for this spacecraft.  It needed 12 switch-mode converters: 10 boosts for the solar array strings, and 2 Cuks for the shunts that bleed off excess power when the battery was full.  I couldn't afford the area and power consumption of 12 discrete controller ICs.  Instead, I built a 12-channel 4-phase controller out of a 4000-series ripple counter, 74-series CMOS flip-flops and LM339 quad comparators.  It is a byzantine gated-oscillator (not PWM!) system, but it runs in a bounded limit cycle and the total chip count is less than 12.

In the late 90's, when all of this was being designed, there was a global shortage of surface-mount tantalum capacitors.  They were all snapped up by manufacturers of cell phones and Internet routers, and a small project like ours just could not buy them.  So what was I to do for bulk capacitance in the power supply?  Aluminum electrolytics were too big, and unsuitable for vacuum.  Ceramic capacitors were my only option.

But I wasn't the only one thinking this.  Very quickly the good military-grade stacked ceramics also disappeared from inventories.  It was even difficult to find high-capacity parts in wide temperature range X7R dielectric.  I was forced to some very low performance dielectrics -- Y5V and Z5U.  These lose capacitance rapidly when hot or cold, so to compensate I needed a lot of physical volume.  I used massive surface-mount chips the size of thumbnails.

These low-grade parts have terrible piezoelectric properties.  As the voltage on the capacitors goes up and down they get physically larger and smaller.  The gated oscillator carrier frequency is 450 kHz, but the converter limit cycles could be down at 10 kHz or so and are a strong function of the battery voltage and load current.  Each capacitor acts like a little speaker, and the combined effect of 12 simultaneous channels of noise meant that everybody in my work area had to wear earplugs when I was testing.

Now MOST is fifteen.  The NiCd batteries lost all of their capacity long ago, but its orbit keeps it in sunlight ten months of each year and the shunts continue to keep the bus voltage regulated.  And I take comfort that the little spacecraft continues to scream outloud with the pure joy of being in space.

Rainbow Rotors

posted Jun 5, 2018, 2:31 PM by Doug Sinclair

We are now making RW3-0.06 wheels in large volume, on slightly different CNC lathes than before.  The new rotors have a beautiful rainbow iridescence to them.  I believe this is because the tooling marks are now spaced by a distance comparable to a wavelength of visible light, causing them to act as a diffraction grating.

High Water Mark

posted May 14, 2018, 6:04 AM by Doug Sinclair

In July of last year, we noted that the order book was momentarily empty.  On January 15 we announced that the order book has closed for flight models for 2018.  Even so, there has been some expansion as outstanding proposals have been accepted and contracts signed.

Today the order book sits at its highest point ever: exactly $9.99M spread over 171 deliverable units.  We have hardware that should ship out to three customers by the end of the month, and I hope we can bring that number back down significantly.

Unsolicited advise for others who may want to start their own business in this field: be prepared for ebbs and flows.  The shot noise in constellation contracts can kill you -- zero is too few, two can be too many, and the various constellation customers are uncorrelated with each other.  But relying on a single customer puts you at the mercy of program slips.  Keep a lot of liquidity on hand, as you may need to ramp up towards a big piece of work that will not pay out for a year.

A Decade of CanX-2

posted May 4, 2018, 12:54 PM by Doug Sinclair

An important milestone passed quietly last week.  On April 28, the CanX-2 satellite marked 10 years on-orbit.  Onboard is the first RW-0.03 reaction wheel, still running nominally.  CanX-2 was the first 3U Cubesat to demonstrate high-performance 3-axis pointing of an optical payload.

All of our 129 reaction wheels currently on-orbit ultimately trace their heritage to the CanX-2 wheel.  We have scaled the design larger and smaller, as different missions have needed, but we have never strayed far from the proven mechanical design that just keeps working.

Alouette Award

posted Apr 11, 2018, 2:47 PM by Doug Sinclair

We were pleased to learn today that the CanX-4/CanX-5 team, including Sinclair Interplanetary, has been selected for the 2018 CASI Alouette Award.  More details can be found in the press release here.

3 mNms Wheel Now Available

posted Jan 19, 2018, 10:41 AM by Doug Sinclair   [ updated Jan 19, 2018, 10:43 AM ]

Those of you who came to the Utah Smallsat Conference in 2017 may have seen an early engineering model of the 3 mNms reaction wheel.  We finally have literature on the website (here).

This is a tiny reaction wheel, but built with the same quality and design philosophy that underlies our larger parts.  We continue to make all of our motors from scratch, carefully controlling our bearing geometry and materials.

A small number of flight-model wheels are currently in inventory (left over from 2017 production), available for immediate sale.

Manufacturing Capacity Full for 2018

posted Jan 15, 2018, 10:37 AM by Doug Sinclair

Sinclair Interplanetary will not be accepting orders for flight equipment from new customers this year.  At the moment we are building ACS equipment for 29 satellites.  That's plenty.  We need to focus on doing that work right before we can take on additional responsibilities.  The order book will re-open on January 1, 2019.

We are currently making flight model RW3-0.06 reaction wheels and ST-16RT2 star trackers in bulk.  This process naturally produces occasional engineering-model units.  They will be offered for sale on this website as they become available.

I am often asked why I don’t expand the company to meet the demand.  We are growing slowly (job ad here still active) but I don’t want to be selfish.  The whole space community benefits when there are many suppliers of complementary products, each with their own ideas and strengths.

Help Wanted

posted Dec 12, 2017, 6:40 AM by Doug Sinclair

Our team is working flat-out, with no respite in sight.  We have hardware for 10 spacecraft in the order book right now, with 30 more expected in 2018.  On top of that, we are rolling out a global optical groundstation network in support of two optical downlink launches next year.  We need help!

Ideally we would like somebody who is qualified in at least three of the following areas:
  1. Technical writer (ICDs/proposals)
  2. Firmware (C/assembly/VHDL)
  3. Digital communications (coding/protocols)
  4. Electronics engineer (digital/analog/power)
  5. High-reliability electronics technician (PCBs/harnesses)
  6. Robotics and controls (kinematics/dynamics/estimation)
  7. Optical designer (space and ground segments)
  8. QA (inspection/configuration management)
This is a full time position in downtown Toronto.  People from all backgrounds will be considered.  Please apply, with resume and a portfolio of things that you have built or flown, to  Clearly identify your areas of expertise.

A bad day

posted Nov 28, 2017, 10:58 AM by Doug Sinclair

Today's Soyuz/Fregat launch failure dropped a great many satellites into the ocean.  Clearly the greatest loss is felt by the owners and users of these spacecraft.  At the subsystem level, this destroyed:
  • 12 Sinclair Interplanetary reaction wheels, of varying sizes
  • 3 Sinclair Interplanetary star trackers
This is the single largest loss of our equipment to date.

Goth baffles in qualification

posted Nov 24, 2017, 5:20 AM by Doug Sinclair

The baffle on the right is our heritage Short Rigid Baffle, with demonstrated 34 degree sun avoidance angle.  It is our 4th generation black coating.

The baffle on the left is our 5th generation black coating.  It is very very black.  In addition, it is free of hexavalent chromium and is thus REACH complaint and can be sold in Europe.  We're still conducting qualification testing on this process, and it's not yet ready for order, but we're very excited.  Retrofit kits for existing customers' baffles will be available upon demand.

Your favourite goth lyrics can be laser engraved on the outside at no extra charge.

You work long hours
Watch your credit rating
Pay your taxes and
Prepare to die

-- "Letters Between a Little Boy and Himself as an Adult", Abney Park

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