Rocket science is not that hard according to a growing band of enthusiasts taking up the rocket building hobby in Australia.

A love of aeronautics and space has attracted more people to start building model rockets using basic kits which can be purchased online.

On weekends you can find the small rockets being launched from a property in the Yass Valley in southern New South Wales.

Canberra Rocketry Group president Nev Blyth has a materials engineering background, but said almost anyone can build model rockets and launch them under safety restrictions.

"We're a bunch of adults and juniors that have a common interest in amateur aerospace and hobby rocketry activities," he said.

"Everything from scale models of rockets that have been used in the past, to contemporary stuff being flown by companies like SpaceX, right through to the technology such as flying electronics and circuits to record altitude or velocity.

"So it [rocket building] caters to a whole bunch of different activities."

Launching all kinds of rockets, large and small

Initially the group met at a local school oval, but moved out to a farm in the Yass Valley for improved safety, with launches up to 4,500 feet or 1,371 metres in height.

Several times a year the club travels to a property near Ardlethan in southern NSW to fire high-powered rockets with larger engines even higher.

Parachutes are packed in to the nose cone of model rockets to ensure a soft return to Earth. ( ABC News: Clarissa Thorpe )

"Now we can cater to all interests from the little rockets which are very easily assembled and cost less than $50 to complete, right through to the larger models where you can easily spend thousands of dollars on parts," he said.

"The actual rockets themselves are made from cardboard tubes, with balsa wood fins and plastic nose cones that are glued together and the only commercial thing is the motors.

"The motors that we use are all commercially manufactured and approved, so there is no backyard chemistry involved."

"There are certainly no wicks like you have in fireworks, these rockets are fired remotely using electronics."

Amateur rocket builder Cary Laue started constructing models almost 30 years ago.

In recent years he has been using a computer simulation program to help design and 'scratch build' rockets.

"I like the science and technology involved in the hobby," he said.

"I love the aspect of being able to build something yourself and to see it work and this case to fly, then recover it and check the data inside.

"When building things like centre of pressure, centre of gravity, thrust and weight ratios all become a part of the componentry, and can be checked in advance using a simulation program.

Mr Laue said his family also supported the hobby and watched his rocket flights on YouTube.

"My sons are now both in their mid-30s but they still get a buzz out of it, but it is my grandchildren, they certainly love seeing them take off."

Rockets that go up must eventually come down

Creating their own rocket and then launching it is exciting for the hobbyists, but model builders also have to think about what happens when gravity takes over.

The models have a parachute packed into the cone to allow a safe return to Earth.

The large scratch-built rocket leaves the launch pad in the Yass Valley on another flight. ( ABC News: Clarissa Thorpe )

"At the highest point it reaches, or apogee, a parachute will be ejected from the nose cone and allow the rocket to come down gently," Mr Blyth said.

"That allows the rocketeer to collect it, repackage the parachute and put a new motor in for another flight.

"The whole idea is that these aren't a one-off thing, and they are designed to be used many, many times and in different configurations."

The rocketry group has several members who work in space-related jobs at the Mount Stromlo Observatory, and in aeronautical and transport safety.

"This is applied science in its pure form," Mr Blyth said.

"And it can lead directly to careers in science and technology, particularly for our junior members just starting out on rocket building."