First you need a patient and loving dog. You will have to put this costume on them many times to get right adjustments
Find an old dog vest to get design from. You may use a dog sweater. I would recommend getting something meant for a dog it will be easier to fit on you dog. I used a vest because it was simple
Lay foil car sun shade on floor or working space. Flip to side that won't be showing. I bought this one for $2 at thrift store
Lay dog clothing on sun shade and outline and cut. You can fine tune it as the costume comes along.
Add a long strip of extra sun shade along the chest area to add for extra support. Then glue gun the Velcro along the end of the strip
Add strips the each side of the vest. Glue Velcro accordingly to the ends. Measure the girth of you dog and area where Velcro may meet. I used large area to put Velcro to ensure stability
It should look something like this. One strap should Velcro to chest plate and then the other strip should Velcro overlapping the first strip
For jet pack I used two old stainless steel water bottles
Or you can spray paint a 2 litter soda bottle instead. I would recommend chrome spray paint. Duck tape your jets to back of vest
Last step use your creativity! I applied flames by gluing them to ends of paper toilet rolls and sticking the rolls in the water bottle. Decorate however you like!
Enjoy turning your pooch into a space adventurer